Plating apparatus and plating method for substrate

ABSTRACT

This invention relates, particularly, to a plating method and apparatus for a substrate for uses, such as the filling of a metal, e.g., copper (Cu), into a fine interconnection pattern (recesses) formed in a semiconductor substrate. The apparatus has a substrate holding portion  36  for horizontally holding and rotating a substrate with its surface to be plated facing upward, a seal material  90  for contacting a peripheral edge portion of the surface, to be plated, of the substrate held by the substrate holding portion  36,  and sealing the peripheral edge portion in a watertight manner, a cathode electrode  88  for passing an electric current upon contact with the substrate, a cathode portion  38  rotating integrally with the substrate holding portion  36,  an electrode arm portion  30  placed above the cathode portion  38  so as to be movable horizontally and vertically and having an anode  98  face-down, and plating liquid pouring means for pouring a plating liquid into a space between the surface, to be plated, of the substrate held by the substrate holding portion  36  and the anode  98  of the electrode arm portion  30  brought close to the surface to be plated. Thus, plating treatment and treatments incidental thereto can be performed by a single unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a plating apparatus and aplating method for a substrate, and more particularly to a platingapparatus and a plating method for a substrate for filling a metal suchas copper (Cu) or the like in fine interconnection patterns (recesses)formed on a semiconductor substrate.

[0003] The present invention also relates to an electrolytic treatmentmethod for applying electrolytic treatment, such as plating or etching,to the surface of a substrate to be treated, and an apparatus therefor.

[0004] The present invention further relates to an electrolytictreatment apparatus for applying, for example, plating or etching to thesurface of a member to be treated, especially, an electrolytic treatmentapparatus and a method for controlling the state of its electric field.

[0005] 2. Description of the Related Art

[0006] Aluminum or aluminum alloy has generally been used as a materialfor forming interconnection circuits on semiconductor substrates. As theintegrated density increases in recent years, there is a demand for theusage of a material having a higher conductivity as an interconnectionmaterial. It has been proposed a method to plate a substrate to fill aninterconnection pattern formed thereon with copper or its alloy.

[0007] There are known various processes including CVD (chemical vapordeposition), sputtering, etc. to fill the interconnection pattern withcopper or its alloy. However, in case of the quality of the material ofthe metal layers is copper or its alloy, i.e., for forming copperinterconnects, the CVD process is costly, and the sputtering processfails to embed copper or its alloy in interconnection pattern having ahigh aspect ratio, i.e., a high ratio of depth to width. The platingprocess is most effective to deposit a metal layer of copper or itsalloy.

[0008] Various processes are available for plating semiconductorsubstrates with copper. They include a process of immersing a substratein a plating liquid held at all times in a plating tank, referred to asa cup-type or dipping-type process, a process of holding a platingliquid in a plating tank only when a substrate to be plated is suppliedto the plating tank, an electrolytic plating process of plating asubstrate with a potential difference, and an electroless platingprocess for plating a substrate with no potential difference.

[0009] Conventionally, a plating apparatus for performing this type ofcopper plating was equipped with a horizontal arrangement of a pluralityof units, such as a unit for performing a pretreatment step incidentalto plating, and a unit for performing a cleaning/drying step afterplating, in addition to a unit for performing a plating step, and atransfer robot for transferring the substrate between these units. Thesubstrate was subjected to a predetermined treatment in each unit whilebeing transferred between the units, and was sequentially transported toa subsequent step after plating treatment.

[0010] In the conventional plating apparatus, however, separate unitswere provided for respective steps, such as plating treatment andpretreatment, and the substrate was transferred to the respective unitsand treated thereby. Thus, there were problems that the apparatus wasconsiderably complicated and difficult to control, occupied a greatarea, and involved a considerably high manufacturing cost.

[0011] With electroplating, moreover, if air bubbles are present in aplating liquid filled between a surface, to be plated, of a substrate(cathode) and an anode, the air bubbles as insulators function as ifthey were anode masks. As a result, the film thickness of a platingformed at positions corresponding to these portions may decrease, or acomplete lack of plating may occur. To obtain a uniform, high qualityplated film, therefore, it is necessary to leave no air bubbles in theplating liquid between the surface, to be plated, of the substrate andthe anode.

[0012] Furthermore, electrolytic treatment, especially electroplating,is widely used as a method for forming a metal film. In recent years,copper electroplating for multilayer interconnects of copper, and goldelectroplating for bump formation, for example, have attracted attentionbecause of their effectiveness (inexpensiveness, hole fillingcharacteristics, etc.), and have found increased use, for instance, inthe semiconductor industry.

[0013]FIG. 71 shows a conventional general constitution of a platingapparatus for applying electroplating onto the surface of a substrate tobe treated (hereinafter referred to as a substrate), such as asemiconductor wafer, by the use of a so-called face-down method. Thisplating apparatus includes a cylindrical plating tank 602 opening upwardand holding a plating liquid 600 therein, and a substrate holder 604 fordetachably holds a substrate W face-down and at such a position that thesubstrate W covers the top opening of the plating tank 602. Inside theplating tank 602, a flat sheet type anode plate 606 immersed in theplating liquid 600 to constitute a anodic electrode is placedhorizontally. On the other hand, an conductive layer S is formed on thelower surface (plating surface) of the substrate W, and this conductivelayer S has at its peripheral edge portion contacts with cathodicelectrodes.

[0014] A plating liquid jet pipe 608 for forming an upwardly directedjet of the plating liquid is connected to the center of the bottom ofthe plating tank 602, and a plating liquid receiver 610 is placed on anupper external portion of the plating tank 602.

[0015] With the above structure, the substrate W held by the substrateholder 604 is placed face-down above the plating tank 602. The platingliquid 600 is gushed upward from the bottom of the plating tank 602 tostrike a jet of the plating liquid 600 on the lower surface (platingsurface) of the substrate W. Simultaneously, a predetermined voltage isapplied between the anode plate 606 (anodic electrode) and theconductive layer S (cathodic electrode) of the substrate W from aplating power source 612 to form a plated film on the lower surface ofthe substrate W. At this time, the plating liquid 600 which hasoverflowed the plating tank 602 is collected from the plating liquidreceiver 610.

[0016] Wafers and liquid crystal substrates for LSI's tend to increasein area year by year. In line with this tendency, variations in the filmthickness of a plated film formed on the surface of the substrate areposing problems. In detail, to supply a cathode potential to thesubstrate, contacts with the electrode are provided in a peripheral edgeportion of the conductive layer formed beforehand on the substrate. Asthe area of the substrate increases, the electric resistance of theconductive layer ranging from the contact on the periphery of thesubstrate to the center of the substrate also increases. As a result, apotential difference produces in the surface of the substrate, causing adifference in the plating speed, thereby leading to variations in thefilm thickness of the resulting plated film.

[0017] That is, to apply electroplating onto the surface of thesubstrate to be treated, common practice is to form an conductive layeron the surface of the substrate to be treated (hereinafter referred tosimply as “substrate”), bring contacts for supplying a cathode potentialinto contact with a site on the conductive layer in proximity to theouter periphery of the substrate W, install an anode at a positionfacing the substrate W, fill a plating liquid between the anode and thesubstrate W, and flow an electric current between the anode and thecontacts by a direct current power source to perform plating on theconductive layer of the substrate W. In the case of a large-areasubstrate, however, the electric resistance of the conductive layerranging from the contact close to the outer periphery of the substrateto the center of the substrate W becomes so high that a potentialdifference arises in the surface of the substrate W, causing differencesin the plating speed among respective portions.

[0018] That is, FIG. 72 is a view showing the film thicknessdistribution of copper plated films over the surface of the substratewhen copper electroplating was performed, using a conventional generalplating apparatus as shown in FIG. 71, on a silicon substrate of 200 mmin diameter having an conductive layer (a copper thin film) with a filmthickness of each of 30 nm, 80 nm and 150 nm formed thereon. FIG. 73 isa view showing the film thickness distribution of copper plated filmsover the surface of the substrate when copper electroplating wassimilarly performed on each of silicon substrates of 100 mm, 200 mm and300 mm in diameter having an conductive layer (a copper thin film) witha film thickness of 100 nm formed thereon. As shown in FIGS. 72 and 73,when the conductive layer is thin, or the diameter of the substrate islarge, there are great variations in the distribution of the filmthickness of the copper plated film formed by electroplating. In extremecases, no copper film may be formed in the vicinity of the center of thesubstrate.

[0019] This phenomenon will be explained electrochemically as follows:

[0020]FIG. 74 shows an electrical equivalent circuit diagram of theconventional general electroplating apparatus shown in FIG. 71. When apredetermined voltage is applied by a plating power source 612 betweenthe anode plate 606 (anodic electrode) submerged in the plating liquid600 and the conductive layer S (cathodic electrode) of the substrate Wto form a plated film on the surface of the conductive layer S, thefollowing resistance components exist in this circuit:

[0021] R1: Power source wire resistance between power source and anode,and various contact resistances

[0022] R2: Polarization resistance at anode

[0023] R3: Plating liquid resistance

[0024] R4: Polarization resistance at cathode (plated surface)

[0025] R5: Resistance of conductive layer

[0026] R6: Power source wire resistance between cathode potentiallead-in contact and power source, and various contact resistances

[0027] As shown in FIG. 74, when the resistance R5 of the conductivelayer S becomes higher than the other electric resistances R1 to R4 andR6, the potential difference producing between both ends of thisresistance R5 of the conductive layer S increases, and accordingly, adifference occurs in the plating current. Thus, the plated film growthrate lowers at a position distant from the cathode lead-in contact. Ifthe film thickness of the conductive layer S is small, the resistance R5further increases, and this phenomenon appears conspicuously.Furthermore, this fact means that the current density differs over thesurface of the substrate, and the characteristics of plating themselves(resistivity, purity, filling characteristics, etc. of the plated film)are not uniform over the surface of the substrate.

[0028] Even in electrolytic etching in which the substrate is an anode,the same problems occur, merely with the direction of electric currentbeing reversed. In a manufacturing process for a large-diameter wafer,for example, the etching rate at the center of the wafer slows comparedwith the peripheral edge portion.

[0029] As a method for avoiding these problems, it is conceivable toincrease the thickness of the conductive layer or decrease the electricconductivity. However, the substrate is subject to various restrictionseven in manufacturing steps other than plating. Furthermore, forexample, when a thick conductive layer is formed on a fine pattern bysputtering, voids easily form inside the pattern. Thus, it is impossibleto easily increase the thickness of the conductive layer or change thefilm type of the conductive layer.

[0030] Placement of the cathode potential lead-in contacts on the entiresurface of the substrate makes it possible to make the potentialdifference over the surface of the substrate small. However, thisplacement is unrealistic for such a reason that the site used as theelectrical contacts cannot be used as LSI. Furthermore, increasing theresistance value of the plating liquid (resistance R3, R2 or R4 in FIG.74) is also effective. However, changing the electrolyte of the platingliquid means changing all of the plating characteristics. Lowering theconcentration of metal ions to be plated, for example, brings about therestriction that the plating speed cannot be made sufficiently high.

[0031] As described above, in the step of performing electroplating byproviding contacts in a peripheral portion of the substrate and usingthe conductive layer on the surface of the substrate, the problem arisesthat as the size of the substrate increases, the plated film thicknessgreatly varies over the surface of the substrate. This problem, inparticular, is a major restriction in the semiconductor industry whichplaces emphasis on the uniformity of the film thickness over the surfaceof the substrate to be treated, and the uniformity of the process.

SUMMARY OF THE INVENTION

[0032] The present invention has been accomplished in view of theabove-described facts. An object of the present invention is to providea plating apparatus and a plating method capable of performing platingtreatment and treatments incidental thereto by a single unit, andfurther a plating apparatus and a plating method for a substrate, whichleave no air bubbles in a plating liquid filled between a surface, to beplated, of the substrate and an anode.

[0033] Another object of the present invention is to provide anelectrolytic treatment apparatus and method capable of performinguniform electrolytic treatment over a surface of a substrate, withoutchanging the thickness and film type of an conductive layer, or anelectrolyte of a plating liquid or the like.

[0034] Still another object of the present invention is to provide anelectrolytic treatment apparatus capable of actively controlling anelectric field state to achieve the desired distribution of the filmthickness over the surface of the substrate, and an electric field statecontrol method for the apparatus.

[0035] According to an invention described in claim 1, there is provideda plating apparatus for a substrate, comprising: a substrate holdingportion for holding the substrate such that a surface, to be plated,thereof faces upward; a cathode electrode for causing current to flow bybeing in contact with the substrate; an anode positioned above thesurface, to be plated, of the substrate; and plating liquid pouringmeans for pouring a plating liquid into a space between the surface, tobe plated, of the substrate held by the substrate holding portion andthe anode brought close to the surface to be plated.

[0036] According to this feature, plating treatment is performed, withthe substrate being held face-up by the substrate holding portion, andthe plating liquid being filled between the surface to be plated and theanode of an electrode arm portion. After plating treatment, the platingliquid is withdrawn from between the plated surface and the anode of theelectrode arm portion, and the electrode arm portion is raised touncover the plated surface. Thus, pretreatment associated with plating,and other treatments, such as cleaning/drying treatment, can beperformed before and after plating treatment, with the substrate beingheld by the substrate holding portion.

[0037] According to an invention described in claim 2, there is providedthe plating apparatus for a substrate according to claim 1, wherein aplating liquid impregnated material composed of a water retainingmaterial is contacted with and held on a lower surface of the anode. Incopper plating, it is common practice to use copper, which containsphosphorus with a content of 0.03 to 0.05% (phosphorus-containingcopper), as an anode in order to suppress the formation of slime. Whenphosphorus-containing copper is used as the anode, what is called ablack film is formed on the surface of the anode, as plating proceeds.In such a case, the plating liquid impregnated material is holding theplating liquid therein to wet the surface of the anode, therebypreventing fall of the black film onto the plated surface of thesubstrate, and simultaneously facilitating extraction of air to theoutside when the plating liquid is poured between the surface, to beplated, of the substrate and the anode.

[0038] According to an invention described in claim 3, there is providedthe plating apparatus for a substrate according to claim 1, comprising:a cathode portion; and a plating liquid tray disposed laterally of thecathode portion; wherein the anode is movable between the cathodeportion and the plating liquid tray. According to this feature, theanode is immersed in the plating liquid in the plating liquid tray andwetted thereby, when plating treatment is not performed. Thus, dryingand oxidation of the black film formed on the anode surface can beprevented.

[0039] According to an invention described in claim 4, there is providedthe plating apparatus for a substrate according to claim 1, comprising:a cathode portion; and a plurality of nozzles disposed laterally of thecathode portion; wherein the nozzles jet a pretreatment liquid, acleaning liquid, a gas or the like toward the surface, to be plated, ofthe substrate held by the substrate holding portion. According to thisfeature, the pretreatment liquid or the cleaning liquid is jetted fromthe nozzles toward the surface to be plated, in a state in which thesubstrate, before and after plating treatment, is held by the substrateholding portion and its surface to be plated is uncovered upwards, andhence pretreatment and cleaning treatment can be performed.

[0040] According to an invention described in claim 5, there is providedthe plating apparatus for a substrate according to claim 1, comprising acathode portion; wherein the substrate holding portion is capable ofascending and descending between a lower substrate transfer position, anupper plating position where a peripheral edge portion of the surface,to be plated, of the substrate contacts the cathode portion, and apretreatment/cleaning position being intermediate between thesepositions. As described above, the substrate holding portion is raisedand lowered so as to correspond to respective operating positions. Thus,more compactness and improved operating properties are achieved.

[0041] According to an invention described in claim 6, there is provideda plating method for a substrate, comprising: sealing a peripheral edgeportion of a surface, to be plated, of the substrate in a watertightmanner, the surface, to be plated, facing upward and being electricallyconnected to a cathode electrode; positioning an anode closely above thesurface, to be plated; and pouring a plating liquid into a sealed spacebetween the surface, to be plated, of the substrate and the anode.

[0042] According to an invention described in claim 7, there is provideda plating method for a substrate, characterized by recovering aremaining plating liquid by a plating liquid recovering nozzle afterplating as recited in claim 6.

[0043] According to an invention described in claim 8, there is providedthe plating method for a substrate according to claim 6, comprising:moving a pre-coating/recovering arm to a position facing the substratebefore plating; and supplying a pre-coating liquid from a pre-coatingnozzle to perform precoating treatment.

[0044] According to an invention described in claim 9, there is providedthe plating method for a substrate according to claim 6, comprising:positioning a plating liquid impregnated material composed of a waterretaining material in a space between a surface, to be plated, of thesubstrate and the anode; and holding the plating liquid inside theplating liquid impregnated material.

[0045] According to an invention described in claim 10, there isprovided a plating apparatus for a substrate, comprising: an anodepositioned above a surface, to be plated, of the substrate held by asubstrate holding portion; and a cathode electrode for causing currentto flow by being in contact with the substrate; wherein a plating liquidimpregnated material composed of a water retaining material ispositioned in a space between the surface to be plated of the substrate,and the anode to perform plating.

[0046] According to an invention described in claim 11, there isprovided the plating apparatus for a substrate according to claim 10,wherein the plating liquid impregnated material is a high resistancestructure.

[0047] According to an invention described in claim 12, there isprovided the plating apparatus for a substrate according to claim 10,wherein the plating liquid impregnated material comprises a ceramic.

[0048] According to an invention described in claim 13, there isprovided a plating apparatus for a substrate, characterized byperforming plating a surface, to be plated, of the substrate in such astate that the plating liquid impregnated material is out of contactwith the surface, to be plated, of the substrate, and a plating liquidis filled into a gap between the plating liquid impregnated material andthe surface, to be plated, of the substrate.

[0049] According to an invention described in claim 14, there isprovided a plating apparatus for a substrate, characterized byperforming plating treatment, and cleaning/drying treatment in a singleunit by raising and lowering the substrate so as to correspond torespective operating positions, with the substrate being held by asubstrate holding portion.

[0050] According to an invention described in claim 15, there isprovided a plating apparatus for a substrate according to claim 14,comprising: an anode positioned above a surface, to be plated, of thesubstrate; and a cathode electrode for causing current to flow by beingin contact with the substrate; wherein a plating liquid impregnatedmaterial composed of a water retaining material is positioned in a spacebetween the surface, to be plated, of the substrate and the anode.

[0051] According to an invention described in claim 16, there isprovided the plating method for a substrate, comprising: transferringthe substrate into a plating unit by a transfer robot after withdrawingthe substrate from a loading/unloading unit housing the substrate;holding the substrate by a substrate holding portion in the platingunit; and performing treatments in a single unit by raising and loweringthe substrate so as to correspond to respective operating positions forperforming plating treatment and cleaning/drying treatment, with thesubstrate being held by the substrate holding portion.

[0052] According to an invention described in claim 17, there isprovided a plating apparatus for a substrate, comprising: aloading/unloading unit housing the substrate; a plating unit forperforming plating treatment and treatment incidental thereto in asingle unit; and a transfer robot for transferring the substrate betweenthe loading/unloading unit and the plating unit.

[0053] According to an invention described in claim 18, there isprovided a plating apparatus for a substrate, comprising: an anodepositioned above a surface, to be plated, of the substrate held by asubstrate holding portion; a cathode electrode for causing current toflow by being in contact with the substrate; and a pure water supplynozzle; wherein the substrate and the cathode electrode aresimultaneously cleaned by supplying pure water from the nozzle aftercompletion of plating.

[0054] According to an invention described in claim 19, there isprovided a plating apparatus for a substrate, comprising: a substrateholding portion for holding the substrate; a cathode electrode forcausing current to flow by being in contact with the substrate held bythe substrate holding portion; an anode positioned closely to thesubstrate; and plating liquid pouring means for pouring a plating liquidinto a space between the surface, to be plated, of the substrate held bythe substrate holding portion and the anode brought close to the surfaceto be plated; wherein the plating liquid pouring means is constitutedsuch that the plating liquid is poured between the anode and thesurface, to be plated, of the substrate from a plating liquid pouringpath provided in part of the anode or provided around an outerperipheral portion of the anode, and is spread on the surface, to beplated, of the substrate.

[0055] According to an invention described in claim 20, there isprovided the plating apparatus for a substrate according to claim 19,comprising: the substrate holding portion for holding the substrate suchthat a surface, to be placed, thereof faces upward; a seal material forholding the plating liquid on the surface, to be plated, of thesubstrate held by the substrate holding portion; a cathode portionhaving a cathode electrode for causing current to flow by being incontact with the substrate; an electrode arm portion, having an anode,movable horizontally and vertically in proximity to the cathodeelectrode; and plating liquid pouring means for pouring a plating liquidinto a space between the surface, to be plated, of the substrate held bythe substrate holding portion and the anode brought close to the surfaceto be plated; wherein the plating liquid pouring means is constitutedsuch that the plating liquid is poured between the anode and thesurface, to be plated, of the substrate from a plating liquid pouringhole provided through part of the anode or a nozzle provided around theouter peripheral portion of the anode, and is spread on the surface, tobe plated, of the substrate.

[0056] According to this features, plating treatment is performed, withthe substrate being held face-up by the substrate holding portion, andthe plating liquid being filled between the surface to be plated and theanode of the electrode arm portion. After plating treatment, the platingliquid is withdrawn from between the plated surface and the anode of theelectrode arm portion, and the electrode arm portion is raised touncover the plated surface. Thus, pretreatment associated with plating,and other treatments, such as cleaning/drying treatment, can beperformed before and after plating treatment, with the substrate beingheld by the substrate holding portion. Furthermore, when the platingliquid is poured between the surface, to be plated, of the substrate andthe anode, a flow of the plating liquid spreading throughout thesurface, to be plated, of the substrate occurs. Along with this flow ofthe plating liquid, air between the surface, to be plated, of thesubstrate and the anode is pushed outward, and enclosure of air by theplating liquid is prevented. Consequently, air bubbles are preventedfrom remaining in the plating liquid filled between the surface, to beplated, of the substrate and the anode.

[0057] According to an invention described in claim 21, there isprovided the plating apparatus for a substrate according to claim 20,wherein the plating liquid pouring means has a plating liquidintroduction path which is provided along a diametrical direction of theanode on a surface of the anode opposite to a surface, facing thesubstrate, of the anode, and is connected to a plating liquid supplypipe, and the plating liquid pouring hole is provided at a positionfacing a plating liquid introduction hole provided so as to open towarda surface of the plating liquid introduction path located at the anodeside. According to this feature, a plating flow occurs in a directionperpendicular to the plating liquid introduction pipe, in accordancewith the pouring of the plating liquid between the surface, to beplated, of the substrate and the anode.

[0058] According to an invention described in claim 22, there isprovided the plating apparatus for a substrate according to claim 19,wherein the plating liquid pouring means has a plating liquidintroduction path which is provided in a cruciform, radial orcircumferential form on a surface of the anode opposite to a surface,facing the substrate, of the anode, and is connected to a plating liquidsupply pipe, and the plating liquid pouring hole is provided at aposition facing a plating liquid introduction hole provided so as toopen toward a surface of the plating liquid introduction path located atthe anode side. According to this feature, a plating flow, which spreadsradially in respective quadrants partitioned by the plating liquidintroduction pipe, occurs in accordance with the pouring of the platingliquid between the surface, to be plated, of the substrate and theanode.

[0059] According to an invention described in claim 23, there isprovided a plating method for a substrate, comprising: positioning ananode closely to at least part of a surface, to be plated, of thesubstrate which is electrically connected to a cathode electrode; andpouring a plating liquid between the surface, to be plated, of thesubstrate and the anode, wherein a plating liquid column which bridgesthe surface, to be plated, of the substrate and the anode is formed andthe plating liquid is poured with the plating liquid column as astarting point.

[0060] According to an invention described in claim 24, there isprovided the plating method for a substrate according to claim 23,wherein the plating liquid is poured between the surface, to be plated,of the substrate and the anode from a plating liquid pouring pathprovided in part of the anode or provided around an outer peripheralportion of the anode.

[0061] According to an invention described in claim 25, there isprovided a plating method for a substrate, comprising: positioning ananode closely to at least part of a surface, to be plated, of thesubstrate which is electrically connected to a cathode electrode; andfilling a plating liquid into a space between the surface, to be plated,of the substrate and the anode, by covering the plating liquid on thesurface, to be plated, of the substrate, and bringing the substrate andthe anode close to each other gradually under relative rotation.According to this feature, air bubbles between the substrate and theanode can be gradually moved outward and driven off, as the substrateand the anode approach each other.

[0062] According to an invention described in claim 26, there isprovided the plating method for a substrate according to claim 25,wherein a plating liquid impregnated material composed of a poroussubstrate having water retaining properties is placed on a surface of aanode facing the substrate; and means for spreading the plating liquidbetween the plating liquid impregnated material and the substrateradially outwardly by relative rotation of the plating liquidimpregnated material and the substrate is provided on a surface of theplating liquid impregnated material facing the substrate. According tothis feature, air bubbles between the substrate and the anode can bedriven off nearly completely.

[0063] According to an invention described in claim 27, there isprovided an electrolytic treatment method, characterized in that a highresistance structure is provided in at least part of an electrolyticsolution filled between a substrate, to be treated, having a contactwith one of electrodes consisting of an anode and a cathode, and theother electrode facing the substrate to be treated, to performelectrolytic treatment of the surface of the substrate to be treated,the high resistance structure having an electrical conductivity lowerthan that of the electrolytic solution.

[0064] According to this feature, the electric resistance between theanode and the cathode submerged in the electrolytic solution is madehigher via the high resistance structure than the electric resistance inthe presence of the electrolytic solution only, so that the differenceof current density over the surface, due to electric resistance, of thesurface of the substrate to be treated can be decreased. In this case,electroplating can be performed by bringing the substrate to be treatedinto contact with the contact of the cathode, or electrolytic etchingcan be performed by bringing the substrate to be treated into contactwith the contact of the anode.

[0065] According to an invention described in claim 28, there isprovided the electrolytic treatment method according to claim 27,wherein the high resistance structure is constituted such that aresistance thereof in an equivalent circuit is higher than a resistancein the equivalent circuit between the contact with the electrode on aconductive layer formed on the surface of the substrate to be treatedand a portion electrically farthest the contact. According to thisfeature, the difference of current density over the surface due toelectric resistance of a conductive layer formed on the substrate to betreated can be made even smaller.

[0066] According to an invention described in claim 29, there isprovided the electrolytic treatment method according to claim 27,wherein the electrolytic treatment is performed in such a state that thesubstrate is held face-up by a substrate holding portion.

[0067] According to an invention described in claim 30, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate to be treated by filling an electrolyticsolution between the substrate, to be treated, having a contact with oneof electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, characterized in that ahigh resistance structure having an electrical conductivity lower thanthat of the electrolytic solution is provided in at least part of theelectrolytic solution.

[0068] According to an invention described in claim 31, there is providethe electrolytic treatment apparatus according to claim 30, wherein theelectrolytic treatment is performed in such a state that substrate isheld face-up by a substrate holding portion.

[0069] According to an invention described in claim 32, there isprovided the electrolytic treatment apparatus according to claim 30,wherein the high resistance structure is constituted such that aresistance thereof in an equivalent circuit is higher than a resistancein the equivalent circuit between the contact with the electrode on aconductive layer formed on the surface of the substrate to be treatedand a portion electrically farthest the contact.

[0070] According to an invention described in claim 33, there isprovided the electrolytic treatment apparatus according to claim 30,wherein the high resistance structure comprises a porous substanceholding an electrolytic solution therein. According to this feature, theelectrical resistance of the high resistance structure can be increasedvia the electrolytic solution which is admitted complicatedly into theporous substance and follows a considerably long path effectively in thethickness direction although the structure is a thin structure.

[0071] According to an invention described in claim 34, there isprovided the electrolytic treatment apparatus according to claim 33,wherein the porous substance comprises a porous ceramic. As the ceramic,alumina, SiC, mullite, zirconia, titania, cordierite, etc. can be citedas examples. To hold the plating liquid stably, moreover, it ispreferably a hydrophilic material. With the alumina-based ceramic, forexample, that with a pore diameter of 10 to 300 μm, a porosity of 20 to60%, and a thickness of about 0.2 to 200 mm, preferably about 2 to 50mm, is used.

[0072] According to an invention described in claim 35, there isprovided the electrolytic treatment apparatus according to claim 30,wherein the high resistance structure is provided so as to divide theelectrolytic solution into a plurality of parts. According to thisfeature, it is possible to use a plurality of the electrolyticsolutions, or prevent contamination or reaction of one of the electrodesfrom exerting influence on the other electrode.

[0073] According to an invention described in claim 36, there isprovided a method for controlling an electric field state in anelectrolytic treatment apparatus, comprising: providing a highresistance structure in at least part of an electrolytic solution filledbetween a substrate, to be treated, having a contact with one ofelectrodes consisting of an anode and a cathode, and the other electrodefacing the substrate to be treated, the high resistance structure havingan electrical conductivity lower than that of the electrolytic solution;and controlling an electric field of a surface of the substrate, to betreated, by adjusting at least one of an exterior shape of the highresistance structure, an internal structure of the high resistancestructure, and an attachment of a member having a different electricalconductivity.

[0074] If the state of the electric field on the surface, to be treated,of the substrate is thus actively controlled to become the desiredstate, a treated state by electrolytic treatment of the substrate to betreated can be made a treated state with a desired distribution over thesurface. In case electrolytic treatment is plating treatment, thethickness of a plated film formed on the substrate to be treated can beuniformized, or an arbitrary distribution can be imparted to thethickness of the plated film formed on the substrate to be treated.

[0075] According to an invention described in claim 37, there isprovided the method of controlling an electric field state in anelectrolytic treatment apparatus according to claim 36, wherein theadjusting of the exterior shape is at least one of adjustment of athickness of the high resistance structure, and adjustment of a shape ona plane of the high resistance structure.

[0076] According to an invention described in claim 38, there isprovided the method of controlling an electric field state in anelectrolytic treatment apparatus according to claim 36, wherein the highresistance structure comprises a porous substance, and the adjusting ofthe internal structure of the porous substance is at least one ofadjustment of a pore diameter distribution thereof, adjustment ofporosity distribution thereof, adjustment of flexing rate distributionthereof, and adjustment of a combination of materials.

[0077] According to an invention described in claim 39, there isprovided the method of controlling an electric field state in anelectrolytic treatment apparatus according to claim 36, wherein theadjusting of attachment of the member having the different electricalconductivity is adjustment of a shielding area of the high resistancestructure by means of the member having the different electricalconductivity.

[0078] According to an invention described in claim 40, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate, to be treated by filling an electrolyticsolution between the substrate, to be treated having a contact with oneof electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, characterized in that: ahigh resistance structure, having an electrical conductivity lower thanthat of the electrolytic solution, is provided in at least part of theelectrolytic solution; and an electric field of a surface of thesubstrate, to be treated, is controlled by adjusting at least one of anexterior shape of the high resistance structure, an internal structureof the high resistance structure, and an attachment of a member having adifferent electrical conductivity.

[0079] According to an invention described in claim 41, there isprovided the electrolytic treatment apparatus according to claim 40,wherein the adjusting of the exterior shape is at least one ofadjustment of a thickness of the high resistance structure, andadjustment of a shape on a plane of the high resistance structure.

[0080] According to an invention described in claim 42, there isprovided the electrolytic treatment apparatus according to claim 40,wherein the high resistance structure comprises a porous substance, andthe adjusting of the internal structure of the porous substance is atleast one of adjustment of a pore diameter distribution thereof,adjustment of porosity distribution thereof, adjustment of flexing ratedistribution thereof, and adjustment of a combination of materials.

[0081] According to an invention described in claim 43, there isprovided the electrolytic treatment apparatus according to claim 40,wherein the adjusting of attachment of the member having the differentelectrical conductivity is adjustment of a shielding area of the highresistance structure by means of the member having the differentelectrical conductivity.

[0082] According to an invention described in claim 44, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate, to be treated, by filling an electrolyticsolution between the substrate, to be treated, having a contact with oneof electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, characterized in that: ahigh resistance structure, having an electrical conductivity lower thanthat of the electrolytic solution, is provided in at least part of theelectrolytic solution; an outer periphery of the high resistancestructure is held by a holding member; and a seal member is providedbetween the high resistance structure and the holding member forpreventing the electrolytic solution from leaking therethrough andpreventing an electric current from flowing.

[0083] As the high resistance structure, alumina porous ceramics orsilicon carbide ceramics can be cited. Moreover, the high resistancestructure may be constituted of a material formed by bundling vinylchloride in a fibrous form, and fusing the fibers together, or amaterial formed by shaping a foam such as polyvinyl alcohol, or a fibersuch as Teflon (trade name) into a form such as a woven fabric or anonwoven fabric. Furthermore, there may be used a composite of any ofthem combined with a conductor and an insulator, or conductors. Besides,the high resistance structure can be composed of a structure havingother type of electrolytic solution sandwiched between two diaphragms.

[0084] According to an invention described in claim 45, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate, to be treated, by filling an electrolyticsolution between the substrate, to be treated, which has a contact withone of electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, comprising: anelectrolytic solution impregnated material is disposed between the otherelectrode and the substrate to be treated; an electrolytic solutionpassing hole is provided in the other electrode for supplying theelectrolytic solution into the electrolytic solution impregnatedmaterial; a pipe is inserted into the electrolytic solution passinghole; and the electrolytic solution supplied into the electrolyticsolution impregnated material through the pipe is supplied from anopposite surface of the electrolytic solution impregnated material andfilled between the electrolytic solution impregnated material and thesubstrate to be treated.

[0085] As the pipe, it is desirable to select a material which is notattacked by the electrolytic solution. Thus, even when the electrolytictreatment step is repeated by this electrolytic treatment apparatus, theinner diameter of the front end of the pipe does not increase with thepassage of time. Hence, the ideal liquid filling state at the initialstage of production is similarly retained with the passage of time.Consequently, the situation that air is engulfed and air bubblesaccumulated between the electrolytic solution impregnated material andthe substrate to be treated can be avoided, and desired electrolytictreatment is always obtained.

[0086] According to an invention described in claim 46, there isprovided the electrolytic treatment apparatus according to claim 45,wherein a electrolytic solution passage portion is provided in theelectrolytic solution impregnated material so as to continue to theelectrolytic solution passing hole.

[0087] According to an invention described in claim 47, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate, to be treated, by filling an electrolyticsolution between the substrate, to be treated, having a contact with oneof electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, characterized in that: anelectrolytic solution impregnated material is disposed between the otherelectrode and the substrate to be treated; an electrolytic solutionpassage portion, having a predetermined depth, is formed in theelectrolytic solution impregnated material; and the electrolyticsolution supplied from the other electrode side into the electrolyticsolution impregnated material through the electrolytic solution passageportion is supplied from an opposite surface of the electrolyticsolution impregnated material and filled between the electrolyticsolution impregnated material and the substrate to be treated. Even whenthe electrolytic treatment step is repeated, the inner diameter of thefront end of the electrolytic solution passage portion does not increasewith the passage of time. Hence, the ideal liquid filling state at theinitial stage of production is similarly retained with the passage oftime. Consequently, the situation that air is engulfed and air bubblesaccumulated between the electrolytic solution impregnated material andthe substrate to be treated can be avoided, and desired electrolytictreatment is always obtained.

[0088] According to an invention described in claim 48, there isprovided the electrolytic treatment apparatus according to claim 47,wherein a liquid reservoir for storing the electrolytic solution isprovided between the other electrode and the electrolytic solutionimpregnated material, and the electrolytic solution stored in the liquidreservoir is supplied into the electrolytic solution impregnatedmaterial.

[0089] According to an invention described in claim 49, there isprovided an electrolytic treatment apparatus for performing electrolytictreatment of a substrate, to be treated, by filling an electrolyticsolution between the substrate, to be treated, having a contact with oneof electrodes consisting of an anode and a cathode, and the otherelectrode facing the substrate to be treated, characterized in that: anelectrolytic solution impregnated material is disposed between the otherelectrode and the substrate to be treated; the electrolytic solutionimpregnated material is constituted such that a passage resistance ofthe electrolytic solution passing through the electrolytic solutionimpregnated material differs according to a location of the electrolyticsolution impregnated material; and the electrolytic solution suppliedfrom the other electrode side into the electrolytic solution impregnatedmaterial is supplied from an opposite surface of the electrolyticsolution impregnated material in a supply amount suited for thelocation, and filled between the electrolytic solution impregnatedmaterial and the substrate to be treated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0090]FIGS. 1A to 1C are sectional views showing an example of a processfor performing plating by the substrate plating apparatus and method ofthe present invention;

[0091]FIG. 2 is a plan view showing the whole of the substrate platingapparatus according to an embodiment of the present invention;

[0092]FIG. 3 is a plan view showing a plating unit;

[0093]FIG. 4 is a sectional view taken on line A-A of FIG. 3;

[0094]FIG. 5 is an enlarged sectional view of a substrate holdingportion and a cathode portion;

[0095]FIG. 6 is a front view of FIG. 3;

[0096]FIG. 7 is a right side view of FIG. 3;

[0097]FIG. 8 is a rear view of FIG. 3;

[0098]FIG. 9 is a left side view of FIG. 3;

[0099]FIG. 10 is a front view showing a precoating/recovering arm;

[0100]FIG. 11 is a plan view of the substrate holding portion;

[0101]FIG. 12 is a sectional view taken on line B-B of FIG. 11;

[0102]FIG. 13 is a sectional view taken on line C-C of FIG. 11;

[0103]FIG. 14 is a plan view of the cathode portion;

[0104]FIG. 15 is a sectional view taken on line D-D of FIG. 14;

[0105]FIG. 16 is a plan view of an electrode arm;

[0106]FIG. 17 is a longitudinal sectional front view of FIG. 16;

[0107]FIG. 18 is a sectional view taken on line E-E of FIG. 16;

[0108]FIG. 19 is an enlarged view showing a part of FIG. 18 in anenlarged manner;

[0109]FIG. 20 is a plan view of a state in which a housing of anelectrode portion of the electrode arm has been removed;

[0110]FIG. 21 is a sectional view schematically showing an initial stageof pouring a plating liquid between a surface, to be plated, of asubstrate and an anode;

[0111]FIG. 22 is a plan view schematically showing a state in which theplating liquid is spreading throughout the surface, to be plated, of thesubstrate;

[0112]FIGS. 23A and 23B are views, corresponding to FIG. 22, showing asecond embodiment of the present invention;

[0113]FIG. 24 is a view, corresponding to FIG. 21, showing a thirdembodiment of the present invention;

[0114]FIG. 25 is a view, corresponding to FIG. 22, showing the thirdembodiment of the present invention;

[0115]FIG. 26 is a view, corresponding to FIG. 21, showing a fourthembodiment of the present invention;

[0116]FIG. 27 is a view, corresponding to FIG. 22, showing the fourthembodiment of the present invention;

[0117]FIG. 28 is a perspective view showing an essential part of a fifthembodiment of the present invention;

[0118]FIG. 29 is a longitudinal sectional front view of the essentialpart of a fifth embodiment of the present invention;

[0119]FIG. 30 is a perspective view showing an essential part of amodification of the fifth embodiment of the present invention;

[0120]FIG. 31A is a front view showing a plating liquid impregnatedmaterial in a sixth embodiment of the present invention, and FIG. 31B isa bottom view of the plating liquid impregnated material;

[0121]FIG. 32A is a front view showing a plating liquid impregnatedmaterial in a seventh embodiment of the present invention, and FIG. 32Bis a bottom view of the plating liquid impregnated material;

[0122]FIG. 33 is a front view showing another use example of theembodiment shown in FIG. 32A;

[0123]FIG. 34 is an enlarged sectional view showing a state of mountingof the plating liquid impregnated material onto the anode;

[0124]FIG. 35 is perspective view of the state of mounting of theplating liquid impregnated material onto the anode;

[0125]FIG. 36 is an enlarged sectional view showing another state ofmounting of the plating liquid impregnated material onto the anode;

[0126]FIG. 37 is an enlarged sectional view showing still another stateof mounting of the plating liquid impregnated material onto the anode;

[0127]FIG. 38 is an enlarged sectional view showing still another stateof mounting of the plating liquid impregnated material onto the anode;

[0128]FIG. 39 is a schematic view of an essential part of anelectrolytic treatment apparatus applied to an electroplating apparatusaccording to still another embodiment of the present invention;

[0129]FIG. 40 is an electrical equivalent circuit diagram of FIG. 39;

[0130]FIG. 41 is a view showing the film thickness distribution of aplated film over a surface of a substrate when plating was performed byeach of the plating apparatus shown in FIG. 39 and a conventionalplating apparatus;

[0131]FIG. 42 is a schematic view of an essential part of anelectrolytic treatment apparatus applied to an electroplating apparatusaccording to still another embodiment of the present invention;

[0132]FIG. 43 is a graph showing changes in the copper ion concentrationof the plating liquid in a region A and a region B when platingtreatment was performed by use of the plating apparatus shown in FIG.42;

[0133]FIG. 44 is a schematic view of an essential part of anelectrolytic treatment apparatus applied to an electroplating apparatusaccording to still another embodiment of the present invention;

[0134]FIG. 45 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0135]FIG. 46 is a view showing the results of measurement of the filmthickness of copper plating in the vicinity of an outer peripheralportion of a substrate W when copper plating was performed on thesubstrate W;

[0136]FIG. 47 is a view showing still another embodiment of the presentinvention;

[0137]FIG. 48 is a view showing still another embodiment of the presentinvention;

[0138]FIG. 49 is a schematic view of an essential part showing a portionclose to an outer peripheral portion of a porous ceramic plate of theelectroplating apparatus;

[0139]FIGS. 50A and 50B are views showing still another embodiment ofthe present invention;

[0140]FIG. 51 is a view showing still another embodiment of the presentinvention;

[0141]FIGS. 52A to 52D are plan views of high resistance structures usedin the electroplating apparatus of FIG. 51;

[0142]FIG. 53 is a view showing still another embodiment of the presentinvention;

[0143]FIG. 54 is a view showing the results of measurement of the platedfilm thicknesses when plating was performed on the substrate W with theuse of the porous ceramic plate having a uniform thickness and theporous ceramic plate having a thickness distribution as shown in FIG.53;

[0144]FIG. 55 is a view showing still another embodiment of the presentinvention;

[0145]FIG. 56 is a view showing still another embodiment of the presentinvention;

[0146]FIG. 57 is a view showing still another embodiment of the presentinvention;

[0147]FIG. 58 is a view showing still another embodiment of the presentinvention;

[0148]FIG. 59 is a view showing still another embodiment of the presentinvention;

[0149]FIGS. 60A and 60B are views showing still another embodiments ofthe present invention;

[0150]FIGS. 61A and 61B are views each showing an example of ananisotropic structural material;

[0151]FIG. 62 is a view showing a face-down type electroplatingapparatus according to still another embodiment of the presentinvention;

[0152]FIG. 63 is a view showing a closed type electroplating apparatusaccording to still another embodiment of the present invention;

[0153]FIG. 64 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0154]FIG. 65 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0155]FIG. 66 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0156]FIG. 67 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0157]FIG. 68 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0158]FIG. 69 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0159]FIG. 70 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention;

[0160]FIG. 71 is a schematic view of a conventional plating apparatus;

[0161]FIG. 72 is a view showing the film thickness distribution of aplated film over a surface of a substrate when copper electroplating wasperformed on a substrate, which had a conductive layer of each ofdifferent film thicknesses, by use of the conventional platingapparatus;

[0162]FIG. 73 is a view showing the film thickness distribution of aplated film over a surface of a substrate when copper electroplating wasperformed on a substrate of each of different sizes by use of theconventional plating apparatus; and

[0163]FIG. 74 is an electrical equivalent circuit diagram of the platingapparatus shown in FIG. 71.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0164] An embodiment of the present invention will be described belowwith reference to the drawings. A substrate plating apparatus accordingto this embodiment is used to apply copper electroplating onto thesurface of a semiconductor substrate, thereby obtaining a semiconductorapparatus having interconnects comprising a copper layer formed thereon.This plating process will be explained with reference to FIGS. 1A to 1C.

[0165] As shown in FIG. 1A, an oxide film 2 of SiO₂ is deposited on theconductive layer 1 a on a semiconductor substrate 1 on whichsemiconductor devices are formed. A contact hole 3 and a trench 4 for aninterconnect are formed by lithography and etching technology. A barrierlayer 5 of TiN or the like is formed thereon, and then a seed layer 7 asan electric supply layer for electroplating is formed on the barrierlayer 105.

[0166] Then, as shown in FIG. 1B, the surface of the semiconductorsubstrate W is coated with copper by copper electroplating to deposit aplated copper film 6 on the oxide film 2, thus filling the contact hole3 and the trench 4 of the semiconductor substrate 1 with copper.Thereafter, the plated copper film 6 on the oxide film 2 are removed bychemical mechanical polishing (CMP), thus making the plated copper film6 in the contact hole 3 and the trench 4 lie flush with the oxide film2. In this manner, an interconnect composed of the plated copper film 6is formed as shown in FIG. 1C.

[0167]FIG. 2 is a plan view showing the whole of a plating apparatus fora substrate according to an embodiment of the present invention. Asshown in FIG. 2, this plating apparatus has a rectangular facility whichhouses therein two loading/unloading units 10 for housing a plurality ofsubstrates W therein, two plating units 12 for performing platingtreatment and treatment incidental thereto, a transfer robot 14 fortransferring substrates W between the loading/unloading units 10 and theplating units 14, and plating liquid supply equipment 18 having aplating liquid tank 16.

[0168] The plated unit 12, as shown in FIG. 3, is provided with asubstrate treatment section 20 for performing plating treatment andtreatment incidental thereto, and a plating liquid tray 22 for storing aplating liquid is disposed adjacent to the substrate treatment section20. There is also provided an electrode arm portion 30 having anelectrode portion 28 which is held at the front end of an arm 26swingable about a rotating shaft 24 and which is swung between thesubstrate treatment section 20 and the plating liquid tray 22.Furthermore, a pre-coating/recovering arm 32, and fixed nozzles 34 forejecting pure water or a chemical liquid such as ion water, and furthera gas or the like toward a substrate are disposed laterally of thesubstrate treatment section 20. In this embodiment, three of the fixednozzles 34 are disposed, and one of them is used for supplying purewater.

[0169] The substrate treatment section 20, as shown in FIGS. 4 and 5,has a substrate holding portion 36 for holding a substrate W with itssurface to be plated facing upward, and a cathode portion 38 locatedabove the substrate holding portion 36 so as to surround a peripheralportion of the substrate holding portion 36. Further, a substantiallycylindrical bottomed cup 40 surrounding the periphery of the substrateholding portion 36 for preventing scatter of various chemical liquidsused during treatment is provided so as to be vertically movable by anair cylinder 42.

[0170] The substrate holding portion 36 is adapted to be raised andlowered by the air cylinder 44 between a lower substrate transferposition A, an upper plating position B, and a pretreatment/cleaningposition C intermediate between these positions. The substrate holdingportion 36 is also adapted to rotate at an arbitrary acceleration and anarbitrary velocity integrally with the cathode portion 38 by a rotatingmotor 46 and a belt 48. A substrate carry-in and carry-out opening 50 isprovided in confrontation with the substrate transfer position A in aframe side surface of the plating unit 12 facing the transfer robot 14,as shown FIG. 7. When the substrate holding portion 36 is raised to theplating position B, a seal member 90 and cathode electrodes 88 (to bedescribed below) of the cathode portion 38 are brought into contact withthe peripheral edge portion of the substrate W held by the substrateholding portion 36. On the other hand, the cup 40 has an upper endlocated below the substrate carry-in and carry-out opening 50, and whenthe cup 40 ascends, the upper end of the cup 40 reaches a position abovethe cathode portion 38 closing the substrate carry-in and carry-outopening 50, as shown by imaginary lines in FIG. 5.

[0171] The plating liquid tray 22 serves to wet a plating liquidimpregnated material 110 and an anode 98 (to be described later on) ofthe electrode arm portion 30 with a plating liquid, when plating has notbeen performed. As shown in FIG. 6, the plating liquid tray 22 is set ata size in which the plating liquid impregnated material 110 can beaccommodated, and the plating liquid tray 22 has a plating liquid supplyport and a plating liquid drainage port (not shown). A photo-sensor isattached to the plating liquid tray 22, and can detect brimming with theplating liquid in the plating liquid tray 22, i.e., overflow, anddrainage. A bottom plate 52 of the plating liquid tray 22 is detachable,and a local exhaust port (not shown) is installed around the platingliquid tray.

[0172] As shown in FIGS. 8 and 9, the electrode arm portion 30 isvertically movable by a motor 54 and a ball screw, not shown, andswingable between the plating liquid tray 22 and the substrate treatmentsection 20 by a motor 56.

[0173] As shown in FIG. 10, the pre-coating/recovering arm 32 is coupledto an upper end of a vertical support shaft 58. Thepre-coating/recovering arm 32 is swingable by a rotary actuator 60 andis also vertically moveable by an air cylinder 62 (see FIG. 7). Thepre-coating/recovering arm 32 supports a pre-coating nozzle 64 fordischarging a pre-coating liquid, on its free end, and a plating liquidrecovering nozzle 66 for recovering the plating liquid, on a portioncloser to its proximal end. The pre-coating nozzle 64 is connected to asyringe that is actuatable by an air cylinder, for example, forintermittently discharging a pre-coating liquid from the pre-coatingnozzle 64. The plating liquid recovering nozzle 66 is connected to acylinder pump or an aspirator, for example, to draw the plating liquidon the substrate from the plating liquid recovering nozzle 66.

[0174] As shown in FIGS. 11 through 13, the substrate holding portion 36has a disk-shaped substrate stage 68 and six vertical support arms 70disposed at spaced intervals on the circumferential edge of thesubstrate stage 68 for holding a substrate W in a horizontal plane onrespective upper surfaces of the support arms 70. A positioning plate 72is mounted on an upper end one of the support arms 70 for positioningthe substrate by contacting the end face of the substrate. A pressingfinger 74 is rotatably mounted on an upper end of the support arm 70which is positioned opposite to the support arm 70 having thepositioning plate 72 for abutting against an end face of the substrate Wand pressing the substrate W the positioning plate 72 side when rotated.Chucking fingers 76 are rotatably mounted on upper ends of the remainingfour support arms 70 c for pressing the substrate W downwardly andgripping the circumferential edge of the substrate W.

[0175] The pressing finger 74 and the chucking fingers 76 haverespective lower ends coupled to upper ends of pressing pins 80 that arenormally urged to move downwardly by coil springs 78. When the pressingpins 80 are moved downwardly, the pressing finger 74 and the chuckingfingers 76 are rotated radially inwardly into a closed position. Asupport plate 82 is disposed below the substrate stage 68 for engaginglower ends of the opening pins 80 and pushing them upwardly.

[0176] When the substrate holding portion 36 is located in the substratetransfer position A shown in FIG. 5, the pressing pins 80 are engagedand pushed upwardly by the support plate 82, so that the pressing finger74 and the chucking fingers 76 rotate outwardly and open. When thesubstrate stage 68 is elevated, the opening pins 80 are lowered underthe resiliency of the coil springs 78, so that the pressing finger 74and the chucking fingers 76 rotate inwardly and close.

[0177] As shown in FIGS. 14 and 15, the cathode portion 38 comprises anannular frame 86 fixed to upper ends of vertical support columns 84mounted on the peripheral edge of the support plate 82 (see FIGS. 5 and13), a plurality of, six in this embodiment, cathode electrodes 88attached to a lower surface of the annular frame 86 and projectinginwardly, and an annular sealing member 90 mounted on an upper surfaceof the annular frame 86 in covering relation to upper surfaces of thecathode electrodes 88. The sealing member 90 is adapted to have an innerperipheral edge portion inclined inwardly downwardly and progressivelythin-walled, and to have an inner peripheral end suspending downwardly.

[0178] When the substrate holding portion 36 has ascended to the platingposition B, as shown FIG. 5, the cathode electrodes 88 are pressedagainst the peripheral edge portion of the substrate W held by thesubstrate holding portion 36 for thereby allowing electric current topass through the substrate W. At the same time, an inner peripheral endportion of the seal member 90 is brought into contact with an uppersurface of the peripheral edge of the substrate W under pressure to sealits contact portion in a watertight manner. As a result, the platingliquid supplied onto the upper surface (surface to be plated) of thesubstrate W is prevented from seeping from the end portion of thesubstrate W, and the plating liquid is prevented from contaminating thecathode electrodes 88.

[0179] In the present embodiment, the cathode portion 38 is verticallyimmovable, but rotatable in a body with the substrate holding portion36. However, the cathode portion 38 may be arranged such that it isvertically movable and the sealing member 90 is pressed against thesurface, to be plated, of the substrate W when the cathode portion 38 islowered.

[0180] As shown in FIGS. 16 through 20, the electrode head 28 of theelectrode arm portion 30 comprises a housing 94 coupled to a free end ofthe swing arm 26 through a ball bearing 92, a cylindrical support frame96 surrounding the housing 94, and an anode 98 fixed by having aperipheral edge portion gripped between the housing 94 and the supportframe 96. The anode 98 covers an opening of the housing 94, which has asuction chamber 100 defined therein. In the suction chamber 100, thereis disposed a diametrically extending plating liquid introduction pipe104 connected to a plating liquid supply pipe 102 which extends from theplating liquid supply unit 18 (see FIG. 2), and held in abutment againstan upper surface of the anode 98. A plating liquid discharge pipe 106communicating with the suction chamber 100 is connected to the housing94.

[0181] The plating liquid introduction pipe 104 is effective to supplythe plating liquid uniformly to the surface to be plated if the platingliquid introduction pipe 104 is of a manifold structure. Specifically,the plating liquid introduction pipe 104 has a plating liquidintroduction passage 104 a extending continuously in its longitudinaldirection, and a plurality of plating liquid introduction ports 104 bspaced at a given pitch along the plating liquid introduction passage104 a and extending downwardly therefrom in communication therewith. Theanode 98 has a plurality of plating liquid supply ports 98 a definedtherein at positions corresponding to the plating liquid introductionports 104 b. The anode 98 also has a number of vertically extendingthrough holes 98 b defined therein over its entire region. The platingliquid that is introduced from the plating liquid supply pipe 102 intothe plating liquid introduction pipe 104 flows through the platingliquid introduction ports 104 b and the plating liquid supply ports 98 ato a position below the anode 98. With the anode 98 being immersed inthe plating liquid, the plating liquid discharge pipe 106 is evacuatedto discharge the plating liquid below the anode 98 via the through holes98 b and the suction chamber 100 from the plating liquid discharge pipe106.

[0182] In order to suppress the generation of slime, the anode 98 ismade of copper containing 0.03 to 0.05% of phosphorus (phosphoruscopper). When the anode 98 is made of phosphorus copper, a black film isformed on the surface of the anode 98 as the plating process progresses.The black film is made of a Cu⁺ complex containing phosphorus and Cl,and comprises Cu₂Cl₂.Cu₂O.Cu₃P, etc. Since the black film suppresses acopper disproportionation reaction, it is important to stably form theblack film on the surface of the anode 98 for the purpose of stabilizingthe plating process. However, if the black film is dried and oxidized,and peeled off the anode 98, then it tends to produce particles.

[0183] In this embodiment, a plating liquid impregnated material 110comprising a water retaining material and covering the entire surface ofthe anode 98 is attached to the lower surface of the anode 98. Theplating liquid impregnated material 110 is impregnated with the platingliquid to wet the surface of the anode 98, thereby preventing a blackfilm from falling onto the plated surface of the substrate by drying,and oxidizing, and simultaneously facilitating escape of air to theoutside when the plating liquid is poured between the surface, to beplated, of the substrate and the anode 98.

[0184] The plating liquid impregnated material 110 has both functions ofretaining liquid and passing liquid therethrough, and has excellentchemical resistance. Specially, the plating liquid impregnated material110 has endurance against an acid plating liquid including sulfuric acidhaving high concentration. The plating liquid impregnated material 110comprises, for example, a woven fabric of polypropylene to preventelution of the impurity in the sulfuric acid solution from having a badinfluence to the plating efficiency (plating speed, resistivity andfilling characteristics). The plating liquid impregnated material 110may comprises at least one material of polyethylene, polyester,polyvinyl chloride, Teflon, polyvinyl alcohol, polyurethane, andderivatives of these materials, other than polypropylene. Nonwovenfabric or sponge-like structure may use in place of woven fabric. Porousceramics and sintered polypropylene made of Alumina and SiC and the likeare available.

[0185] That is, many fixing pins 112 each having a head portion at thelower end are arranged such that the head portion is provided in theplating liquid impregnated material 110 so as not to be releasableupward and a shaft portion of the fixing pin pierces the interior of theanode 98, and the fixing pins 112 are urged upward by U-shaped platesprings 114, whereby the plating liquid impregnated material 110 isbrought in close contact with the lower surface of the anode 98 by theresilient force of the plate springs 114 and is attached to the anode98. With this arrangement, even when the thickness of the anode 98gradually decreases with the progress of plating, the plating liquidimpregnated material 110 can be reliably brought in close contact withthe lower surface of the anode 98. Thus, it can be prevented that airenters between the lower surface of the anode 98 and the plating liquidimpregnated material 110 to cause poor plating.

[0186] Incidentally, columnar pins made of PVC (polyvinyl chloride) orPET and having a diameter of, for example, about 2 mm may be arrangedfrom the upper surface side of the anode so as to pierce the anode, andan adhesive may be applied to the front end surface of each of the pinsprojecting from the lower surface of the anode to fix the anode to theplating liquid impregnated material.

[0187] When the impregnated material has a sufficient strength such as aporous ceramics, the anode may be placed on the impregnated materialwithout using pins for fixing the impregnated material.

[0188] When the substrate holding portion 36 is in the plating positionB (see FIG. 5), the electrode head 28 is lowered until the gap betweenthe substrate W held by the substrate holding portion 36 and the platingliquid impregnated material 110 becomes about 0.5 to 3 mm, for example.Then, the plating liquid is supplied from the plating liquid supply pipe102 to fill the gap between the upper surface, to be plated, of thesubstrate W and the anode 98 while impregnating the plating liquidimpregnated material 110 with the plating liquid, thus plating the uppersurface of the substrate W.

[0189] At this time, shown in FIG. 21, at positions approximatelycorresponding to the plating liquid supply ports 98 a of the anode 98,the plating liquid reaches the upper surface (surface to be plated) ofthe substrate W from the lower surface of the plating liquid impregnatedmaterial 110, thereby forming plating liquid columns 120 which bridgethe plating liquid impregnated material 110 and the surface, to beplated, of the substrate W. By continuing the supply of the platingliquid, the plating liquid columns 120 are gradually grown, or connectedto each other. Then a flow of the plating liquid Q, which advances in adirection perpendicular to the plating liquid introduction pipe 104 andspreads over the entire surface of the surface, to be plated, of thesubstrate W, occurs as shown in FIG. 22.

[0190] As a result, air bubbles B entrained by this flow of the platingliquid Q are pushed outward, and a front line Q₁ of the flow of theplating liquid Q is a nearly straight line, so that the plating liquid Qdoes not enclose air. Thus, the air bubbles are prevented from remainingin the plating liquid filled between the plating liquid impregnatedmaterial 110 and the surface, to be plated, of the substrate W.

[0191] As shown in FIG. 4, stopper bars 116 are erected outwardly of thesupport columns 84 supporting the cathode portion 38. Protrusions 96 aprovided on the periphery of the support frame 96 are brought intocontact with the upper surfaces of the stopper bars 116, whereby thedescent of the electrode portion 28 is controlled.

[0192] A plating process carried out by the substrate plating apparatusaccording to the above embodiment will be described below.

[0193] First, a substrate W to be plated is taken out from one of theloading/unloading units 10 by the transfer robot 14, and transferred,with the surface to be plated being oriented upwardly, through thesubstrate carry-in and carry-out opening 50 defined in the side panel,into one of the plating units 12. At this time, the substrate holdingportion 36 is in the lower substrate transfer position A. After the handof the transfer robot 14 has reached a position directly above thesubstrate stage 68, the hand of the transfer robot 14 is lowered toplace the substrate W on the support arm 70. The hand of the transferrobot 14 is then retracted through the substrate carry-in and carry-outopening 50.

[0194] After the hand of the transfer robot 14 is retracted, the cup 40is elevated. Then, the substrate holding portion 36 is lifted from thesubstrate transfer position A to the pretreating/cleaning position C. Asthe substrate holding portion 36 ascends, the substrate W placed on thesupport arms 70 is positioned by the positioning plate 72 and thepressing finger 74 and then reliably gripped by the fixing fingers 76.

[0195] On the other hand, the electrode head 28 of the electrode armportion 30 is in a normal position over the plating liquid tray 22 now,and the plating liquid impregnated material 110 or the anode 98 ispositioned in the plating liquid tray 22. At the same time that the cup40 ascends, the plating liquid starts being supplied to the platingliquid tray 22 and the electrode head 28. Until the step of plating thesubstrate W is initiated, the new plating liquid is supplied, and theplating liquid discharge pipe 106 is evacuated to replace the platingliquid in the plating liquid impregnated material 110 and remove airbubbles from the plating liquid in the plating liquid impregnatedmaterial 110. When the ascending movement of the cup 40 is completed,the substrate carry-in and carry-out opening 50 in the side panel isclosed by the cup 40, isolating the atmosphere in the side panel and theatmosphere outside of the side panel from each other.

[0196] When the cup 40 is elevated, the pre-coating step is initiated.Specifically, the substrate holding portion 36 that has received thesubstrate W is rotated, and the precoating/recovering arm 32 is movedfrom the retracted position to a position confronting the substrate W.When the rotational speed of the substrate holding portion 36 reaches apreset value, the pre-coating nozzle 64 mounted on the tip end of thepre-coating/recovering arm 32 intermittently discharges a pre-coatingliquid which comprises a surface active agent, for example, toward thesurface to be plated of the substrate W. At this time, since thesubstrate holding portion 36 is rotating, the pre-coating liquid spreadsall over the surface to be plated of the substrate W. Then, theprecoating/recovering arm 32 is returned to the retracted position, andthe rotational speed of the substrate holding portion 36 is increased tospin the pre-coating liquid off and dry the surface to be plated of thesubstrate W.

[0197] After the completion of the pre-coating step, the plating step isinitiated. First, the substrate holding portion 36 is stopped againstrotation, or the rotational speed thereof is reduced to a presetrotational speed for plating. In this state, the substrate holdingportion 36 is lifted to the plating position B. Then, the peripheraledge of the substrate W is brought into contact with the cathodeelectrodes 88, when it is possible to pass an electric current, and atthe same time, the sealing member 90 is pressed against the uppersurface of the peripheral edge of the substrate W, thus sealing theperipheral edge of the substrate W in a water-tight fashion.

[0198] Based on a signal indicating that the pre-coating step for theloaded substrate W is completed, the electrode arm portion 30 is swungin a horizontal direction to displace the electrode head 28 from aposition over the plating liquid tray 22 to a position over the platingposition. After the electrode head 28 reaches this position, theelectrode head 28 is lowered toward the cathode portion 38. At thistime, the plating liquid impregnated material 110 does not contact withthe surface to be plated of the substrate W, but is held closely to thesurface to be plated of the substrate W at a distance ranging from 0.5mm to 3 mm. When the descent of the electrode head 28 is completed, aplating current is supplied, and the plating liquid is supplied from theplating liquid supply pipe 102 into the electrode head 28, and then fromthe plating liquid supply ports 98 a through the anode 98 to the platingliquid impregnated material 110.

[0199] As a result, plating liquid columns 120 which bridge the platingliquid impregnated material 110 and the surface, to be plated, of thesubstrate W are formed at positions approximately corresponding to theplating liquid supply ports 98 a of the anode 98. By continuing thesupply of the plating liquid, the plating liquid columns 120 aregradually grown, and tied to each other. The resulting flow advances ina direction perpendicular to the plating liquid introduction pipe 104and spreads over the entire surface, to be plated, of the substrate W.Thus, air bubbles on board this flow of the plating liquid are pushedoutward, and the plating liquid does not enclose air. Hence, the airbubbles are prevented from remaining in the plating liquid residingbetween the plating liquid impregnated material 110 and the surface, tobe plated, of the substrate W. Consequently, the plating liquidcontaining copper ions, which has seeped from the plating liquidimpregnated material 110, is filled into a gap between the platingliquid impregnated material 110 and the surface, to be plated, of thesubstrate W without leaving air bubbles. By this measure, copper platingis performed on the surface, to be plated, of the substrate. At thistime, the substrate holding portion 36 may be rotated at a low speed.

[0200] While the plating liquid is being poured, it is preferred toapply a constant voltage between the substrate W and the anode 98. By sodoing, an electric current of a constant density can be flowed throughthe plating liquid contact portion, and when an appropriate voltage isselected, the copper seed layer of the substrate W can be protected frometching.

[0201] Further, the plating liquid may be supplied from the platingliquid supply ports 98 a to the plating liquid impregnated material 110during plating treatment to pour the plating liquid between the platingliquid impregnated material 110 and the surface, to be plated, of thesubstrate W. Simultaneously, the plating liquid may be sucked anddischarged through the plating liquid discharge pipe 106. As a result,the plating liquid filled between the substrate W and the anode 98 maybe circulated and stirred during the plating treatment, whereby airbubbles in the plating liquid can be extracted. The pouring/suction ofthe plating liquid may be performed throughout the plating time, ratherthan at the initial stage of plating only.

[0202] When the supply of the plating liquid continues, the platingliquid containing copper ions, which has seeped out of the platingliquid impregnated material 110, is filled into the gap between theplating liquid impregnated material 110 and the surface, to be plated,of the semiconductor substrate W so that copper plating is performed onthe surface, to be plated, of the substrate. At this time, the substrateholding portion 36 may be rotated at a low speed.

[0203] When the plating treatment is completed, the electrode armportion 30 is raised and then swung to return to the position above theplating liquid tray 22 and to lower to the ordinary position. Then, thepre-coating/recovering arm 32 is moved from the retreat position to theposition confronting to the semiconductor substrate W, and lowered torecover the remainder of the plating liquid on the substrate W by aplating liquid recovering nozzle 66. After recovering of the remainderof the plating liquid is completed, the precoating/recovering arm 32 isreturned to the retreat position, and pure water is supplied from thefix nozzle 34 for supplying pure water toward the central portion of thesubstrate W for rinsing the plated surface of the substrate. At the sametime, the substrate holding portion 36 is rotated at an increased speedto replace the plating liquid on the surface of the substrate W withpure water. Rinsing the substrate W in this manner prevents thesplashing plating liquid from contaminating the cathode electrode 88 ofthe cathode portion 38 during descent of the substrate holding portion36 from the plating position B.

[0204] After completion of the rinsing, the washing with water step isinitiated. That is, the substrate holding portion 36 is lowered from theplating position B to the treatment/cleaning position C. Then, whilepure water is supplied from the fixed nozzle 34 for supplying purewater, the substrate holding portion 36 and the cathode portion 38 arerotated to perform washing with water. At this time, the seal member 90and the cathode electrodes 88 can also be cleaned, simultaneously withthe substrate W, by means of pure water directly supplied to the cathode38, or pure water scattered from the surface of the substrate W.

[0205] After washing with water is completed, the drying step isinitiated. That is, supply of pure water from the fixed nozzle 34 isstopped, and the rotational speed of the substrate holding portion 36and the cathode portion 38 is further increased to remove pure water onthe surface of the substrate W by centrifugal force and to dry thesurface of the substrate W. The seal member 90 and the cathodeelectrodes 88 are also dried at the same time. Upon completion of thedrying, the rotation of the substrate holding portion 36 and the cathodeportion 38 is stopped, and the substrate holding portion 36 is loweredto the substrate transfer position A. Thus, the gripping of thesubstrate W by the fixing fingers 76 is released, and the substrate W isjust placed on the upper surfaces of the support arms 70. At the sametime, the cup 40 is also lowered.

[0206] All the steps including the plating step, the pretreating stepaccompanying to the plating step, the cleaning step, and the drying stepare now finished. The transfer robot 14 inserts its hand through thesubstrate carry-in and carry-out opening 50 into the position beneaththe substrate W, and raises the hand to receive the processed substrateW from the substrate holding portion 36. Then, the transfer robot 14returns the processed substrate W received from the substrate holdingportion 36 to one of the loading/unloading units 10.

[0207] By the way, when plating treatment is performed, with the platingliquid impregnated material being attached to the lower surface of theanode as in this embodiment, air bubbles may enter inside the poresformed in the plating liquid impregnated material 110. Such air bubblesact as insulators, becoming the cause of disturbing the electric currentdistribution during plating treatment. To overcome this trouble, it iseffective to suck the plating liquid discharge pipe 106 prior to platingtreatment, thereby decompressing the space where the plating liquidimpregnated material 110 is placed, and then to introduce the platingliquid from the plating liquid introduction pipe 104 into the platingliquid impregnated material 110. By this way, outward escape of the airbubbles entering the interior of the pores of the plating liquidimpregnated material 110 can be promoted. The resulting uniform currentdistribution enables high quality plating to be achieved. Thistreatment, if performed at the start-up of the plating apparatus, iseffective, because that can remove air bubbles that have entered thepores of the plating liquid impregnated material 110 from the first.

[0208] In this embodiment, while the substrate W is being held, with itssurface upward, by the substrate holding portion, the plating step andother steps including the pretreatment and cleaning/drying stepsassociated with the plating step can be carried out before and after theplating step. Therefore, all the steps of the plating process can becarried out by the single plating apparatus, which can provide theplating apparatus which is simplified and takes up a small installationarea cheaply. Since the plating apparatus can be installed as a platingunit on another semiconductor fabrication apparatus, it providesadvantages in clustering a series of interconnects forming stepsincluding plating, annealing, and CMP.

[0209] Here, as shown in FIG. 23A, the plating liquid introduction pipe104 which has blade portions extending cruciformly in directionsperpendicular to each other and which has plating liquid introductionports 104 b at predetermined positions along the longitudinal directionof each blade portion may be used, and the anode (not shown) which hasplating liquid supply ports 98 a at positions corresponding to theplating liquid introduction ports 104 b may be used. In this case, inthe same manner as described above, plating liquid columns which bridgethe plating liquid impregnated material and the surface, to be plated,of the substrate W are formed at positions approximately correspondingto the plating liquid supply ports 98 a of the anode. As the supply ofthe plating liquid continues, the plating liquid columns gradually grow.Then, a flow of the plating liquid Q, which spreads radially inquadrants defined by the plating liquid introduction pipe 104, isgenerated and the plating liquid Q spreads over the entire surface ofthe surface, to be plated, of the substrate W.

[0210] As shown in FIG. 23B, a similar flow of the plating liquid Q isgenerated, when the plating liquid introduction pipes 104 are placed ina concentric manner and communicated with each other, and plating liquidintroduction ports 104 b are provided at predetermined positions. Theplating liquid introduction ports 104 b of the plating liquidintroduction pipe 104 may be provided at equal pitch and with equaldiameter, but discharge of the liquid may be controlled by adjusting thepitch of the ports and the diameter of the ports.

[0211] In addition, as shown in FIGS. 24 and 25, one or a plurality ofplating liquid supply ports 98 a may be provided concentrically at anend portion of the anode 98, and the plating liquid may be introducedsimultaneously into the respective plating liquid supply ports 98 a. Inthis case, in the same manner as described above, plating liquid columns120 which bridge the plating liquid impregnated material 110 and thesurface, to be plated, of the substrate W are formed at positionsapproximately corresponding to the plating liquid supply ports 98 a ofthe anode 98. As the supply of the plating liquid continues, the platingliquid columns gradually grow. Then, a flow of the plating liquid Q,which flows in one direction toward the opposite side, occurs, and theplating liquid Q spreads over the entire surface, to be plated, of thesubstrate W.

[0212] Besides, as shown in FIGS. 26 and 27, the anode 98 may be placedin an inclined state relative to the substrate W, with the substrate Wbeing held horizontally. A plating liquid supply port 98 a is providedat a position in the anode 98 close to the substrate W. The platingliquid is introduced into the plating liquid supply port 98 a, and theanode 98 is gradually fallen toward the substrate W so as to behorizontal to the substrate W, simultaneously. In this case, in the samemanner as described above, a plating liquid column 120 which bridges theplating liquid impregnated material 110 and the surface, to be plated,of the substrate W is formed at a position corresponding to the platingliquid supply port 98 a of the anode 98. As the inclination anglebetween the anode 98 and the substrate W gradually decreases, a flow ofthe plating liquid Q, which spreads in one direction between the anode98 and the surface, to be plated, of the substrate W, occurs, and theplating liquid Q spreads over the entire surface, to be plated, of thesubstrate W.

[0213] Alternatively, contrary to the above, the anode side may beplaced horizontally, while the substrate may be inclined relative to theanode side, and simultaneously with pouring of the plating liquid, thesubstrate may be gradually fallen so as to be horizontal to the anodeside.

[0214]FIGS. 28 and 29 show the anode 98 and the plating liquidimpregnated material 110 according to another embodiment of the presentinvention. That is, in this embodiment, the plating liquid impregnatedmaterial 110 is composed of porous ceramics such as alumina, SiC,mullite, zirconia, titania or cordierite, or a hard porous material suchas a sintered compact of polypropylene or polyethylene, or a compositematerial comprising these materials. In case of the alumina-basedceramics, for example, the ceramics with a pore diameter of 30 to 200μm, a porosity of 20 to 95%, and a thickness of about 5 to 20 mm,preferably 8 to 15 mm, are used.

[0215] The plating liquid impregnated material 110 has a flange portion110 a provided at the upper portion thereof, and is fixed by holdingthis flange portion 110 a between the housing 94 and the support frame96 (see FIG. 17 and 18). The anode 98 is placed and held on the uppersurface of the plating liquid impregnated material 110. In thisembodiment, the anodes of various shapes, such as porous ones ormesh-like ones may be placed.

[0216] As described above, in the case where the plating liquidimpregnated material 110 is composed of a porous material, theelectrical resistance of the interior of the plating liquid impregnatedmaterial 110 can be increased by the plating liquid which hascomplicatedly entered the plating liquid impregnated material 110. Thus,the thickness of the plated film can be uniformized, and the generationof particles can be prevented. Furthermore, the anode 98 is placed andheld on the plating liquid impregnated material 110. Thus, even when theside of the lower surface of the anode 98 which is in contact with theplating liquid impregnated material 110 is dissolved with the progressof plating, the distance between the lower surface of the anode 98 andthe substrate W can be kept constant by the own weight of the anode 98without the use of a jig for fixing the anode 98, and air accumulationcaused by air entering therein can be prevented.

[0217] In this embodiment, a plating liquid introduction pipe 104 of acruciform shape extending in a diametrical direction in the same manneras shown in FIG. 22 is installed on the upper surface of the anode 98.Plating liquid supply ports 98 a of the anode 98 are provided atpositions corresponding to plating liquid introduction ports 104 bprovided in the plating liquid introduction pipe 104. Many through holes98 b are provided in the anode 98.

[0218] In this embodiment, there is shown an example in which the anode98 is placed and held on the upper surface of the plating liquidimpregnated material 110. However, the plating liquid impregnatedmaterial 110 and the anode 98 may be placed at spaced apart positions.In this case, when a soluble anode is used as the anode 98, the anode isdissolved from its lower portion. Thus, as time passes, the gap betweenthe anode and the plating liquid impregnated material may enlarge andform a gap in the range of 0 to about 20 mm.

[0219] According to the present embodiment, at positions approximatelycorresponding to the plating liquid supply ports 98 a of the anode 98,the plating liquid reaches the upper surface (surface to be plated) ofthe substrate W from the lower surface of the plating liquid impregnatedmaterial 110, thereby forming the plating liquid columns 120 whichbridge the liquid impregnated material 110 and the surface, to beplated, of the substrate W. At this time, when the plating liquid flowsinside the plating liquid impregnated material 110, the plating liquidis slightly diffused along its flow direction, thereby alleviatingdamage to the seed layer 5 (see FIG. 1A) upon arrival of the platingliquid at the substrate W, namely, alleviating the phenomenon of theseed layer due to local application of a jet, and thus contributing tothe uniformity of the film thickness during a subsequent plating step.

[0220] As indicated by imaginary lines in FIG. 29, after the platingliquid reaches the upper surface (surface to be plated) of the substrateW from the lower surface of the plating liquid impregnated material 110to form the plating liquid columns 120, the substrate W, for example,may be instantaneously raised to bring the plating liquid impregnatedmaterial 110 and the substrate W close to each other instantaneously.Further, it is possible to form the plating liquid columns 120 similarlywhile bending the substrate in a concave form under slight pressure onthe edge of the substrate, and then to release the pressure, therebyrestoring the substrate to the original shape. With this measure, theplating liquid impregnated material 110 and the substrate W may beinstantaneously brought close to each other.

[0221] When the plating liquid impregnated material 110 has a largethickness and a high density (low porosity), for example, resistancebecomes large when the plating liquid flows inside the plating liquidimpregnated material 110. As a result, a predetermined amount of theplating liquid does not flow out of the plating liquid impregnatedmaterial 110, and binding of the plating liquid columns 120 isdisturbed. Even if air is dragged at this time, a rapid outward flow ofthe plating liquid can be generated to drive out air bubbles togetherwith the plating liquid, and the supply of the plating liquid betweenthe plating liquid impregnated material 110 and the substrate W can beperformed in a short time by being brought the plating liquidimpregnated material 110 and the substrate W instantaneously close toeach other.

[0222] Contact between the plating liquid and the seed layer 5 (see FIG.1A) in a non-energized state induces a decrease in the seed layer 5.Even in an energized state, the failure of the plating liquid to spreadon the surface of the substrate W in a short time causes variations inthe film thickness at the initial stage of plating, and impairs theuniformity of subsequent plated film thickness. However, these troublescan be prevented by supplying the plating liquid between the platingliquid impregnated material 110 and the substrate W in a short time.

[0223] Further, as shown in FIG. 28, the plating liquid may be suppliedfrom the plating liquid supply ports 98 a to the plating liquidimpregnated material 110 during plating treatment to pour the platingliquid between the plating liquid impregnated material 110 and thesurface, to be plated, of the substrate W. Simultaneously, the platingliquid in the same amount as the amount of the poured plating liquid canbe sucked and discharged via the through holes 98 b through a platingliquid discharge pipe 106.

[0224] The plating liquid is stirred in this manner during platingtreatment, whereby it becomes possible to remove air bubbles which havenot been withdrawn during liquid filling, and air bubbles which haveoccurred during plating treatment after liquid filling.

[0225] In the present plating apparatus, the spacing between thesurface, to be plated, of the substrate W and the anode 98 is small, sothat a small amount of the plating liquid to be used is sufficient.However, since the additives and ions in the plating liquid become inlimited amounts, in order to perform efficient plating in a short time,it is necessary to distribute the additives and the like uniformly inthe plating liquid. In this respect, according to the presentembodiment, because the plating liquid is stirred during platingtreatment, it is possible to perform plating in such a state that theadditives and ions are distributed uniformly.

[0226] As shown in FIG. 30, additive introduction pipes 105, ofsubstantially the same constitution as the plating liquid introductionpipe 104 and having an additive introduction path 105 a and additiveintroduction ports 105 b, may be further provided on the upper surfaceof the anode 98. Additive pouring holes 98 c may be provided atpositions of the anode 98 corresponding to the additive introductionports 105 b. A liquid containing additives, such as a leveler and acarrier, and ions (a plating liquid) may be supplied intermittently orcontinuously from the additive pouring holes 98 c during platingtreatment. By this measure, the additives and ions consumed by platingmay be supplemented. In this case, the additives are in tiny amounts, sothat the plating liquid need not be discharged through the through holes98 b. Furthermore, the proportions of the components of the additivesmay be varied during plating, whereby the level difference of the filmthickness between the line and space portion (interconnects portion) andthe flat portion can be decreased, and the CMP characteristics in asubsequent step can be improved.

[0227]FIGS. 31A and 31B, and FIGS. 32A and 32B show different otherembodiments of the present invention in which the plating liquidimpregnated material 110 is composed of a hard porous material. In theseembodiments, means for causing radial outward spread of the platingliquid between the plating liquid impregnated material 110 and thesubstrate W by their relative rotation is provided on the lower surfaceof the plating liquid impregnated material 110. Other constitutions arethe same as in the embodiment shown in FIGS. 28 and 29.

[0228] That is, in FIGS. 31A and 31B, a plurality of spiral projections(blades) 110 b curved outward along a rotating direction are provided onthe lower surface of the plating liquid impregnated material 110. InFIGS. 32A and 32B, the lower surface of the plating liquid impregnatedmaterial 110 is per se formed as a tapered surface 110 c having a taper,for example, of about {fraction (1/100)} and bulging downward at thecenter.

[0229] In these embodiments, after plating liquid columns 120 whichbridge the plating liquid impregnated material 110 and the surface, tobe plated, of the substrate W are formed, the substrate W is rotated,for example, to rotate the plating liquid impregnated material 110 andthe substrate W relative to each other. In accordance with thisrotation, the plating liquid between the plating liquid impregnatedmaterial 110 and the substrate W is caused to spread radially outwardlywhile being agitated. As a result, air bubbles B having entered betweenthe plating liquid impregnated material 110 and the substrate W aredriven outward forcibly together with the plating liquid. At the sametime, supply of the plating liquid between the plating liquidimpregnated material 110 and the substrate W can be performed in a shorttime.

[0230] Particularly, as shown in FIGS. 31A and 31B, the projections 110b having a flow-arranging action for assisting in the spread of theplating liquid, and an agitating action associated with rotation areprovided on the lower surface of the plating liquid impregnated material110. Consequently, the limited additives and ions in the plating liquidcan be distributed uniformly on the surface of the substrate W.

[0231] Instead of the spiral projections 10 b shown in FIGS. 31A and31B, there may be provided projections widening outwardly radially.Instead of such projections, depressions (grooves) may be provided.Alternatively, an arc-shaped round surface may be used instead of thetapered surface 110 c shown in FIGS. 32A and 32B.

[0232] Further, as shown in FIG. 33, a plating liquid may be fedbeforehand on the surface, to be plated, of a substrate W having aperipheral edge portion sealed in a watertight manner with a sealmaterial 90. The plating liquid impregnated material 110 having a lowersurface like the tapered surface 110 c shown in FIGS. 32A and 32B may,for example, be lowered while being rotated. By this measure, theplating liquid impregnated material 110 and the substrate W may begradually brought close to each other while being relatively rotated,whereby the plating liquid may be filled between the plating liquidimpregnated material 110 and the substrate w. By so doing, air bubbles Bbetween the plating liquid impregnated material 110 and the substrate Wcan be gradually moved outward and reliably driven off, as the platingliquid impregnated material 110 and the substrate W approach each other.As a result, the space between the plating liquid impregnated material110 and the substrate W can be filled with the plating liquid free fromair bubbles.

[0233] In the respective embodiments above, examples in which thesubstrate is held face-up are shown. However, it goes without sayingthat the vertical relationship between the substrate and the anode isnot restricted thereto.

[0234] According to the plating apparatus of this embodiment, platingtreatment, pretreatment incidental to plating treatment, and othertreatments such as cleaning/drying treatment can be performed before andafter plating treatment, with the substrate being held face-up by thesubstrate holding portion. Thus, simplification of the apparatus can beachieved, and the plating apparatus occupying only a small area can beprovided inexpensively. In addition, the space between the surface, tobe plated, of the substrate and the anode can be filled with the platingliquid, with no air bubbles remaining. Thus, a uniform and high qualityplated film can be formed on the surface to be plated.

[0235] As shown in FIGS. 34 and 35, a number of substantially columnarfixing pins 112 each having a large-diameter head portion 112 a at thelower end are placed such that the head portions 112 a are buried andfixed in the plating liquid impregnated material 110 so as not to beescapable upward, and a shaft portions of the pins are inserted intothrough-holes 98 c provided in the interior of the anode 98, and areprotruded upward. Moreover, the fixing pins 112 are urged upward, forexample, via U-shaped plate springs 114 of synthetic resin, whereby theplating liquid impregnated material 110 is attached to the lower surfaceof the anode 98 in an intimately contacted via the resilient force ofthe plate springs 114.

[0236] In this embodiment, slits 110 a of a predetermined depth areprovided on a lower surface side of the plating liquid impregnatedmaterial 110. Each of the shaft portion 112 a of the fixing pin 112 ispositioned in this slit 110 a, and the shaft portion is stuck into theplating liquid impregnated material 110, whereby the fixing pin 112 isfixed to the plating liquid impregnated material 110. The plating liquidimpregnated material 110 is returned to close the slits 110 a by itsresilient force.

[0237] The material for the fixing pin 112 is, for example,polypropylene, PEEK, PVC or polyethylene, but these materials, needlessto say, are not restrictive, and any material having sufficientdurability to the plating liquid and sufficient strength as the pin maybe used. The diameter of the fixing pin 112 is, for example, about 0.5to 4 mm. The mounting pitch for the fixing pins 112 differs according tothe plating liquid impregnated material 110 that is used, the platingarea, etc. With plating of an 8-inch substrate, for example, themounting pitch is about 5 to 40 mm, and the number of the fixing pinsmounted is about 10 to 150. Desirably, the mounting pitch is 20 mm, andthe number of the fixing pins mounted is about 50 to 100.

[0238] Because of such constitutions, the lower surface of the anode 98where a black film is formed is wetted with the plating liquid held bythe plating liquid impregnated material 110. Moreover, the platingliquid impregnated material 110 plays the role of a filter, so that thedrying and dropout of the black film, and further, oxidation can beprevented. In addition, even when the anode 98 gradually dissolves andfades and its thickness decreases with the progress of plating, theanode 98 and the plating liquid impregnated material 110 are always keptin close contact under the resilient force of the plate springs 114.Thus, formation of air accumulation between them is prevented. Normally,the anode 98 is consumed in an amount of about 20 to 40 mm as a resultof one month of plating.

[0239] As shown in FIG. 36, there may be used the fixing pin 112 whichhas a fishhook-like portion 112 b at the lower end. This fishhook-likeportion 112 b may be pushed in from the upper surface side of theplating liquid impregnated material 110, and hooked on and fixedthereto. Further, the fixing pin 112 may be urged upward, for example,using a coil spring 120 of synthetic resin. A plate spring is moreadvantageous than the coil spring in terms of the mounting method andprice.

[0240] Besides, as shown in FIG. 37, columnar fixing pins 112 of PVC(polyvinyl chloride) or PET, for example, of about 2 mm in diameter maybe placed from the upper surface side of the anode so as to be insertedinto the through-holes 98 c of the anode 98, and an adhesive 122 may beapplied to each of the front end surface of the fixing pins 112appearing on the lower surface of the anode 98 to adhere and fix to theplating liquid impregnated material 110. As the adhesive 122, a vinylchloride-based adhesive, a silicon modified polymer adhesive, arubber-based adhesive, or a cyanoacrylate-based adhesive can be cited.Needless to say, however, they are not restrictive, and any adhesivesmay be used, if they are durable to the plating liquid, and minimal insolving-out of organic substances and occurrence of particles.

[0241] Further, as shown in FIG. 38, a pinnacle-shaped portion 112 c maybe provided at the front end of the fixing pin 112 to make it convenientfor the fixing pin 112 to be stuck into the plating liquid impregnatedmaterial 110. In this case, as shown in FIG. 38, pinhole-like slits 110a may be provided on the lower surface side of the plating liquidimpregnated material 110.

[0242]FIG. 39 is a schematic view of an essential part of anelectrolytic treatment apparatus applied to an electroplating apparatusaccording to still another embodiment of the present invention. FIG. 40is an electrical equivalent circuit diagram thereof. This apparatusholds a silicon substrate (hereinafter referred to as a substrate) of200 mm in diameter in a so-called face-down manner, and applies copperplating onto its surface (lower surface). A thin film of sputteredcopper as a conductive layer (seed layer) S is formed, for example witha film thickness of 100 nm, on the lower surface (surface to be plated)of this substrate W.

[0243] This plating apparatus includes a cup-shaped plating tank 212opening upward and holding a copper sulfate-based plating liquid 210therein. A doughnut-shaped anode plate 214 having a central hole 214 a,for example, of 30 mm in diameter is installed at the bottom of theplating tank 212. The material of this anode plate 214 is coppercontaining 0.04% by weight of phosphorus, for example. Around theplating tank 212, a plating liquid receiver 216 is placed for recoveringthe plating liquid 210 that has overflowed from the top of the platingtank 212.

[0244] On the peripheral portion of the substrate W, a lip seal 218,which makes pressure contact with the peripheral edge portion of thelower surface of the substrate W to inhibit outflow of the platingliquid 210 from this site, is provided above the plating tank 212.Outwardly of the lip seal 218, contacts 220 are provided for contactingthe substrate W to introduce a cathode potential into the substrate W.

[0245] Inside the plating tank 212, a high resistance structure 222 of alower electrical conductivity than the electrical conductivity of theplating liquid 210 is placed between the anode plate 214 and thesubstrate W. The high resistance structure 222, in this embodiment, isconstituted, for example, by holding the plating liquid 210 in a porousceramic plate 224 of alumina having a porosity of 30%, an average porediameter of 100 μm and a thickness T₁ of 20 mm. That is, the porousceramic plate 224 per se is an insulator, but the high resistancestructure 222 is constituted by causing the plating liquid 210 to enterits interior complicatedly and follow a considerably long path in thethickness direction. That is, the flexing rate of pores formed in aporous ceramic plate is high. Thus, compared with many holes formed inan insulator with a thickness d, pores in the porous ceramic plate withthe same thickness d constitute a long path measuring 2 d to 3 d. Atpositions of the porous ceramic plate 224 facing the central hole 214 aof the anode plate 214, a plurality of through-holes 224 a, for example,of 1 mm in diameter are provided with 5 mm pitch. The porous ceramicplate 224 may be in intimate contact with the anode plate 214, or may bein intimate contact with the substrate W.

[0246] According to the above constitution, the substrate W is placedface-down above the plating tank 212, and the plating liquid 210 isgushed upward from the bottom of the plating tank 212 through thecentral hole 214 a of the anode plate 214 and the through-holes 224 a ofthe porous ceramic plate 224 to strike a jet of the plating liquid 210on the lower surface (surface to be plated) of the substrate W. Duringthis action, a predetermined voltage from a plating power source 226 isapplied between the anode plate 214 (anodic electrode) and an conductivelayer S (cathodic electrode) of the substrate W, whereby a plated filmis formed on the lower surface of the substrate W. At this time, theplating liquid 210 that has overflowed into the plating tank 212 isrecovered from the plating liquid receiver 216.

[0247] Using the plating apparatus of this embodiment, electroplatingwith copper was performed, with the current density set at 20 mA/cm² andthe distance L between the upper surface of the anode plate 214 and thelower surface of the substrate W set at 50 mm. A power supply voltagenecessary for plating increased by about 2V compared with that beforeinstallation of the porous ceramic plate 224. This increase results fromthe fact that the porous ceramic plate 224 functioned as a resistor witha lower electrical conductivity than the plating liquid 210.

[0248] That is, the cross sectional area of the plating tank 212 isabout 300 cm², so that the resistance of the high resistance structure222 is about 0.333 Å. In the equivalent circuit shown in FIG. 40,therefore, a resistance Rp generated by this high resistance structure222 is added as a new resistance. In FIG. 40, the resistances R1 to R5show the same resistance values as the resistances R1 to R5 shown inFIG. 74.

[0249] When the great resistance Rp adds because of the high resistancestructure 222, the ratio of the resistance at the center of thesubstrate to the resistance in the peripheral portion, namely,(R2+Rp+R3+R4)/(R2+Rp+R3+R4+R5), approaches 1. Hence, the influence ofthe resistance R5 of the conductive layer becomes a negligible degree.Consequently, the difference in current density over the surface of thesubstrate due to electrical resistance on the surface of the substrate Wbecomes small, and the uniformity of the plated film over the surface ofthe substrate improves.

[0250] The resistance value of a high resistance structure 222 is 0.01 Åor more, preferably 0.01 to 2 Å, more preferably 0.03 to 1 Å, and evenmore preferably 0.05 to 0.5 Å, for example, in the case of a 200 mmwafer. The resistance value of this high resistance structure 222 ismeasured by the following procedure: First, in the plating apparatus, adirect current (I) of a predetermined value is flowed between bothelectrodes comprising the anode plate 214 and the substrate W spaced bya predetermined distance to perform plating, and the voltage (V1) of thedirect current power source at this time is measured. Then, in the sameplating apparatus, the high resistance structure of a predeterminedthickness is placed between both electrodes, and a direct current (I) ofthe same value is flowed to perform plating. At this time, the voltage(V2) of the direct current power source is measured. With this method,the resistance value Rp of the high resistance structure can becalculated from Rp (V2−V1)/I. In this case, the purity of copperconstituting the anode plate is preferably 99.99% or more. The distancebetween the two electrode plates comprising the anode plate and thesubstrate is preferably in the range of 5 to 25 mm in the case of thesubstrate having a diameter of 200 mm, and is preferably in the range of15 to 75 mm in the case of the substrate having a diameter of 300 mm.The resistance R5 of the conductive layer S on the substrate W can bedetermined by measuring the resistance value between the outer peripheryand the center of the substrate with the use of a tester, or calculatedfrom the resistivity of the material and the thickness of the conductivelayer S.

[0251]FIG. 41 shows the film thickness distribution of a plated filmover a surface of a substrate when copper plating was performed on thesurface of the substrate W with the use of a plating apparatus havingthe high resistance structure 222 comprising the porous ceramic plate224 installed therein as described earlier (present embodiment example),and a plating apparatus without the high resistance structure(conventional example). FIG. 41 shows that a thin film phenomenon at thecenter of the substrate did not take place in the plating apparatus ofthis embodiment, but uniform plating was performed.

[0252] On the other hand, the resistivity of the plating liquid is about5.5 Å·m and the cross sectional area of the plating tank 212 is about300 cm². Thus, if it is attempted to obtain the same effect, i.e., aresistance of about 0.333 Åusing the plating liquid 210, by increasingthe distance between the substrate W and the anode plate 214, there isneed to separate them by an additional distance of about 18 cm, thusresulting in the upsizing of the apparatus.

[0253] In this embodiment, an example in which the high resistancestructure is constituted of an alumina porous ceramic plate is shown.However, other materials, such as silicon carbide ceramics, have alsobeen confirmed to obtain the same effect. The porosity, the porediameter, the flexing rate of pores, etc. can be selected, as desired,according to the purpose. In this embodiment, for example, the 1 mmthrough-holes were bored in the porous ceramic plate to promotecirculation of the plating liquid, but this will be unnecessary, if thepore diameter is large.

[0254] Moreover, the use of a material formed by bundling vinyl chloridein a fibrous form, and fusing them together can obtain a plate havinglarge amounts of holes rectilinearly piercing in the thicknessdirection. The high resistance structure may be constituted of such aplate. Alternatively, the high resistance structure may be constitutedof a material formed by shaping foam such as polyvinyl alcohol, or afiber such as Teflon (trade name) into a form such as a woven fabric ora nonwoven fabric. Furthermore, the same effect can be obtained by useof a composite of any of them combined with a conductor and aninsulator, or conductors.

[0255] Any of these high resistance structures can be subjected, asdesired, to pretreatment before being assembled into the platingapparatus. Especially, acid pickling, degreasing, or joint washing withthe plating liquid or a component in the plating liquid is effective.The thickness and shape of the high resistance structure can, of course,be changed, as desired, unless the change departs from the gist of thepresent invention.

[0256] In this embodiment, electroplating has been described. However,if the direction of electric current is reversed, in other words, if theapparatus is used unchanged, and the polarity of the power source isreversed, electrolytic etching can be performed. In this case,uniformity of etching can be improved. With plating process for copperinterconnects in LSI, it is known to perform electrolytic etching whileapplying reverse electrolysis before and after the plating process. Forexample, using this apparatus, plating is performed for 7.5 seconds at acurrent density of 20 mA/cm² to form a 50 nm copper plated film, andthen etching is performed for 20 seconds at a current density of 5mA/cm², with the polarity of the power source being reversed to etch thecopper plated film 33 nm thick, followed by performing final plating. Inthis manner, it has been confirmed that etching is carried outuniformly, and embedding characteristics are improved.

[0257]FIG. 42 shows an electrolytic treatment apparatus applied toelectroplating according to still another embodiment of the presentinvention. This plating apparatus adapts to a so-called face-up system,in which a substrate W is placed on a substrate placing stand 230 so asto face upward. On the periphery of the substrate W, a lip seal 234, forexample, of Bayton rubber is provided. Outwardly of the lip seal 234,contacts 236 are provided for contacting an conductive layer S of thesubstrate W to introduce a cathode potential into the substrate W. Thelip seal 234, for example at a height of 10 mm, can hold a platingliquid 210.

[0258] A holding tool 232 is arranged above the substrate placing stand230. An anode plate 238, and a porous ceramic plate 242 constituting ahigh resistance structure 240 are held on and fixed to the holding tool232 with a predetermined spacing provided therebetween. The porousceramic plate 242, in this embodiment, is a SiC plate, for example,having a porosity of 20%, an average pore diameter of 50 μm and athickness T₂ of 10 mm, and holding the plating liquid 210 therein,thereby constituting the high resistance structure 240. The anode plate238 is of a structure completely covered with the holding tool 232 andthe porous ceramic plate 242. The porous ceramic plate 242, desirably,is impregnated with the plating liquid, beforehand, in a separate tank(not shown) storing the plating liquid.

[0259] A first plating chamber 244 with a gap S₁ set at about 2 mm isprovided between the upper surface of the substrate W and the lowersurface of the porous ceramic plate 242, and a second plating chamber246 with a gap S₂ set at about 1.5 mm is provided between the uppersurface of the porous ceramic plate 242 and the lower surface of theanode plate 238. The plating liquid 210 is introduced into these platingchambers 244, 246. A method adopted for introducing the plating liquid210 is to introduce the plating liquid 210 from a gap between the lipseal 234 and the end surface of the porous ceramic plate 242, orintroduce the plating liquid 210, which has been pressurized, to therear side (upper portion) of the porous ceramic plate 242 via athrough-hole provided in the anode plate 238.

[0260] In this embodiment, the substrate W and the substrate placingstand 230, or the anode plate 238 and the porous ceramic plate 242 maybe rotated during electroplating.

[0261] Copper plating was performed on the upper surface (surface to beplated) of the substrate W with the use of the plating apparatus of thisembodiment, and the film thickness of the resulting copper plated filmwas examined. By providing the high resistance structure 240 composed ofthe porous ceramic plate 242, it has been confirmed that the uniformityof the film thickness over the surface of the substrate is improved asin the aforementioned embodiment.

[0262] This embodiment has a structure in which the anode plate 238 iscompletely covered with the porous ceramic plate 242 and the holdingtool 232, and the plating liquid 210 is filled between the anode plate238 and the porous ceramic plate 242. The apparatus is so structured,and the porosity, flexing rate, pore diameter, etc. of the porousceramic plate 242 are suitably selected, whereby an unprecedented noveleffect can be obtained.

[0263]FIG. 43 shows changes in the copper ion concentration of theplating liquid 210 when plating treatment for 300 seconds (2 μm) wasperformed by use of the electroplating apparatus of this embodiment. InFIG. 43, a region A represents data on the plating liquid 210 within theplating chamber 244 between the porous ceramic plate 242 and thesubstrate W, while a region B represents data on the plating liquid 210within the plating chamber 246 between the anode plate 238 and theporous ceramic plate 242.

[0264] As shown in FIG. 43, in the region A, the copper ionconcentration decreases as plating proceeds. The decrease rate agreeswith the theoretical values of the copper ions consumed on the substratesurface by plating. In the region B, on the other hand, the copper ionconcentration increases, and the increase rate agrees with thetheoretical values of the copper ions generated on the anode plate.

[0265] From the above facts, it is seen that copper ion exchangeminimally takes place between the region A (plating chamber 244) and theregion B (plating chamber 246) sandwiching the porous ceramic plate 242,showing that the porous ceramic plate 242 behaves like a diaphragm. Inother words, the reaction occurring on the anode side does not affectthe substrate side.

[0266] Normally, special considerations should be given to the anodeduring copper electroplating. First, phosphorus-containing copper shouldbe used as the material for anode, out of the necessity for forming agluey black-colored film, called black film, on the surface of the anodefor capturing monovalent copper ions generated from the anode. Thisblack film is said to be a composite of copper, phosphorus and chlorine,and acts to feed only divalent copper ions into the plating liquid andcapture monovalent copper ions which become the cause of abnormalprecipitation on the plating surface.

[0267] According to the plating apparatus of this embodiment, copper ionexchange between the regions above and below the porous ceramic plate242 does not occur, as clear from FIG. 43. Thus, such considerationsbecome unnecessary. Moreover, the anode plate 238 of copperelectrolytically wastes away in accordance with plating, and its surfacemay fall off. The falling-off matter is captured by the porous ceramicplate 242, and does not deposit on the plated surface of the substrateW. Furthermore, instead of using a dissolvable copper anode as anode,there can be used an undissolvable anode, for example, having iridiumoxide coated on the surface of titanium. In this case, a large amount ofan oxygen gas is generated on the surface of the anode. However, theoccurrence of a defect, such as part of the plated film falling off, canbe eliminated by preventing this oxygen gas from arriving at the surfaceof the substrate.

[0268] As described above, the diaphragm effect can be obtained byintroducing a suitable substance having a low electrical conductivityinto the plating liquid, and arranging this substance between the anodeand the cathode uniformly so as to separate the anode and the cathode.

[0269]FIG. 44 shows an electrolytic treatment apparatus applied to agold electroplating apparatus according to still another embodiment ofthe present invention. This plating apparatus includes a box-shapedplating tank 250. One opening end of this plating tank 250 is closed,for example, with an undissolvable anode plate 252 having a titaniumbase material coated with iridium oxide, while the other opening endthereof is openably and closably closed with a cover body 254 holding asubstrate W on the plating tank 250 side. At an end portion of the coverbody 254 facing the plating tank 250, a lip seal 256 is provided formaking pressure contact with the substrate W, and inhibiting outflow ofthe plating liquid 210 from this site. Outwardly of the lip seal 256,contacts 258 are provided for contacting a conductive layer S of thesubstrate W to introduce a cathode potential into the substrate W.

[0270] Inside the plating tank 250, two diaphragms 260 a, 260 b areplaced and held by meshes 262 a, 262 b, which are provided beforehand inthe plating tank 250, so as to separate the substrate W and the anodeplate 252. As the diaphragms 260 a, 260 b, a strongly acidic cationexchange membrane, e.g., Tokuyama's CMS or Du Pont's N-350, is used.

[0271] As a result, a plating chamber 264 facing the substrate W, anelectrolytic solution chamber 266 facing the anode plate 252, and a highresistance electrolytic solution chamber 268 sandwiched between thediaphragms 260 a and 260 b are partitioned and formed inside the platingtank 250. Furthermore, individual liquid circulation paths are providedwith each of these chambers 264, 266 and 268.

[0272] A plating liquid 270, for example, based on gold potassiumcyanide is introduced into the plating chamber 264, and an electrolyticsolution (plating liquid) 272, for example, comprising an aqueoussolution of sulfuric acid (80 g/l) is introduced into the electrolyticsolution chamber 266. These liquids are circulated, for example, at arate of 20 liters per minute. A high resistance electrolytic solution274 with low electrical conductivity, which comprises, for example, anaqueous solution of diluted sulfuric acid (10 g/l), is introduced intothe high resistance electrolytic solution chamber 268, without beingsubject to restrictions by plating treatment. By this arrangement, ahigh resistance structure 276 is constituted.

[0273] As described above, the high resistance structure 276,constituted by filling the high resistance electrolytic solution 274,such as an aqueous solution of diluted sulfuric acid, into the highresistance electrolytic solution chamber 268 partitioned by the twodiaphragms 260 a and 260 b, is interposed between the plating liquids270 and 272, whereby the plating resistance of the entire system can beincreased, and the film thickness distribution of the gold plated filmover the surface of the substrate due to the resistance of theconductive layer can be decreased markedly. In this embodiment,moreover, the resistance value of the plating system can be selectedarbitrarily by changing the concentration of the diluted sulfuric acidsolution, so that the plating conditions can be changed, as desired,according to the type of plating, status of the substrate, and so on.

[0274] This plating apparatus forms a plated film by holding thesubstrate W by the cover body 254, closing the cover body 254,introducing the plating liquid 270 into the plating chamber 264 and theelectrolytic solution (plating liquid) 272 into the electrolyticsolution chamber 266, circulating these liquids, respectively, fillingthe high resistance electrolytic solution chamber 268 with the highresistance electrolytic solution 274, and flowing a plating currentbetween the anode plate 252 and the conductive layer S on the substrateW from an external power source (not shown), while keeping these states.An oxygen gas 278 generating on the surface of the anode plate 252 isdischarged to the outside together with the electrolytic solution(plating liquid) 272.

[0275] In this embodiment as well, the same effect can be obtained bymaking the distance between the anode plate and the substrate very greatto heighten the electrical resistance of the plating liquid per se.However, doing so makes the apparatus huge, and also expensive goldpotassium cyanide for gold plating has to be used in a massive amount.Thus, industrial disadvantage becomes great.

[0276] In the above embodiment, the disk-shaped substrate is used as thesubstrate to be treated, but the substrate need not necessarily bedisk-shaped, and needless to say, may be rectangular.

[0277] According to the electrolytic treatment apparatus of thisembodiment, the electrical resistance between the anode and the cathodeimmersed in the electrolytic solution is made higher via the highresistance structure than that when the interior comprises theelectrolytic solution alone. Thus, the difference of the current densityover the surface of the substrate due to the electrical resistance onthe surface of the substrate to be treated can be made small, so thatthe uniformity over the surface of the substrate to be treated byelectrolytic treatment can be increased further.

[0278] [Embodiment using Insulating Member as Electric Field StateControl Means]

[0279]FIG. 45 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. The electroplating apparatus shown in FIG. 45 is anelectroplating apparatus adopting a so-called face-up system, and asubstrate W is placed face upward on a substrate placing stand 330. Theperiphery of the substrate W is in contact with, and sealed with, thefront end of a lip seal 334 formed like a ring. A plating liquid 310 isfilled inwardly of the lip seal 334. Outwardly the lip seal 334 locatedon the face side of the substrate W, contacts 336 are disposed incontact with an conductive layer on the surface of the substrate W toapply a cathode potential to the substrate W.

[0280] Above the substrate W, a disk-shaped high resistance structure340 and a disk-shaped anode plate 338 are arranged via a predeterminedgap, and held by a holding member 332. The anode plate 338 is providedwith many narrow holes 339 passing therethrough in the thicknessdirection. Above the anode plate 338, a plating liquid introduction pipe341 for supplying a plating liquid to the narrow holes 339 in adistributed manner is installed.

[0281] The high resistance structure 340, in this embodiment, isconstituted by holding the plating liquid 310 in a porous ceramic plate(e.g., a plate of SiC with a porosity of 20%, an average pore diameterof 50 Ωm, and a thickness of 10 mm) 342. The anode plate 338 iscompletely covered with the holding member 332 and the porous ceramicplate 342.

[0282] In the embodiment, a band-like insulating member 350 is woundaround an outer peripheral side surface of a porous ceramic plate(porous substance) 342. As the material of the insulating member 350, anextensible material such as fluororubber is cited.

[0283] A plating liquid, which has been supplied under pressure from aplating liquid introduction pipe 341 to the porous ceramic plate 340through the narrow holes 339 of an anode plate 338, permeates theinterior of the porous ceramic plate 342 and is delivered from its lowersurface. As a result, the interior of the porous ceramic plate 342 and aspace between the substrate W and the porous ceramic plate 342 arefilled with the plating liquid. Introduction of the plating liquid maybe performed from a gap between a lip seal 334 and an end surface of theporous ceramic plate 342. In this case, neither the plating liquidintroduction pipe 341 nor the narrow holes 339 of the anode plate 338are necessary.

[0284] In this state, when a predetermined voltage is applied betweenthe anode plate 338 and the substrate W to flow a direct current,plating (e.g. copper plating) is applied on the entire surface of theconductive layer of the substrate W. According to the presentembodiment, the porous ceramic plate 342 is interposed between the anodeplate 338 and the substrate W, and hence there is minimal influence dueto the difference among the resistance values of the respective portionsaccording to the difference in the distance from contacts 336 on thesurface of the substrate W as stated above. Consequently, substantiallyuniform plating (e.g. copper plating) is applied on the entire surfaceof the conductive layer of the substrate W.

[0285] However, portions in the vicinity of the outer peripheral portionclose to the contacts 336 are still high in current density, and tend tobe thicker in plated film thickness than other portions.

[0286] In the present embodiment, therefore, an insulating member 350 iswound around the outer peripheral side surface of the porous ceramicplate 342 to prevent an electric current from concentrating at an areanear the outer peripheral portion of the substrate W, as shown by dottedlines in FIG. 45, thereby decreasing the current density at such areaand making it nearly equal to the current density directed toward theother portions of the substrate W.

[0287]FIG. 46 is a view showing the results of measurement of the filmthickness of copper plating in the vicinity of an outer peripheralportion of a substrate W when copper plating was performed on thesubstrate W using the above-described method. As shown in FIG. 46, it isseen that the film thickness of copper plating in the vicinity of theouter peripheral portion of the substrate W is varied by changing thewidth L of the insulating member 350 (see FIG. 45). That is, as thewidth L increases, the current density in the vicinity of the outerperipheral portion of the substrate W lowers, and the plated filmthickness decreases. Hence, the insulating member 350 having the desiredwidth L (e.g., L=4 mm) is used, whereby the plated film thickness in thevicinity of the outer peripheral portion of the substrate W can be madethe same as that in other portions. As noted from this, the insulatingmember 350 serves to adjust the shielding area of the outer peripheralside surface of the porous ceramic plate 340 by the length of the widthL. However, the shielding area by the insulating member 350 may beadjusted not only by the width L, but also by boring holes in theshielding material per se.

[0288] The present invention is not necessarily used when making theplated film thickness in the vicinity of the outer peripheral portion ofthe substrate W the same as the plated film thickness in other portions.If it is desired to make the plated film thickness in the vicinity ofthe outer peripheral portion of the substrate W larger than in otherportions, for example, the width L of the insulating member 350 may bemade small. If an opposite case is desired, the width L may be madelarge. That is, according to this embodiment, the plated film thicknessin the vicinity of the outer peripheral portion of the substrate W canbe freely controlled to a desired value.

[0289]FIG. 47 is a view showing still another embodiment of the presentinvention. The difference of this embodiment from the embodiment shownin FIG. 45 is that a movable, tubular insulating member 350 a isinstalled on the outer periphery of the porous ceramic plate 342,instead of mounting the band-like insulating member 350. This insulatingmember 350 a is provided at the lower end of an insulating member holder351. The insulating member holder 351 is adapted to be movable upwardand downward by an upwardly/downwardly moving drive mechanism (notshown). By so constituting, the position of the insulating member 350 ais moved upward or downward to change its relative position against tothe porous ceramic plate 342, thereby adjusting the exposure area of theouter peripheral side surface of the porous ceramic plate 342. By thismeasure, the current density in the vicinity of the outer peripheralportion of the substrate W can be arbitrarily controlled. Consequently,the plated film thickness in the vicinity of the outer peripheralportion of the substrate W can be adjusted arbitrarily, like theembodiment shown in FIG. 45.

[0290]FIG. 48 is a view showing still another embodiment of the presentinvention. The difference of this embodiment from the embodiment shownin FIG. 45 is that an insulating member 350 b is provided by coating orpermeating the outer peripheral side surface of the porous ceramic plate342 with an insulating material, instead of mounting the band-likeinsulating member 350. For example, the insulating member 350 b isprovided by permeating the outer peripheral side surface of the porousceramic plate 342 with an insulating material, such as glass, resin orsilicone. In this case, the current density in the vicinity of the outerperipheral portion of the substrate W can be arbitrarily controlled byadjusting the width of permeating area and the distribution of thepermeating depth. Consequently, the plated film thickness in thevicinity of the outer peripheral portion of the substrate W can beadjusted arbitrarily, like the embodiment shown in FIG. 45. Furthermore,it is also possible to control the current density by oxidizing part ofthe base material (e.g., SiC).

[0291] [Embodiment using Seal Member]

[0292]FIG. 49 is a schematic view of an essential part showing portionsin the vicinity of the outer peripheral portion of a porous ceramicplate 342 of an electroplating apparatus having the same structure asthat shown in FIG. 45. However, the insulating member 350 shown in FIG.45 is not shown in this electroplating apparatus. In this electroplatingapparatus, since a gap between a holding member 332 and the porousceramic plate 340 is not sealed, a plating liquid flows out of the anodeplate 338 through the gap between a holding member 332 and the porousceramic plate 340 to form a passage for an electric current as shown byan arrow. Since this current passage is such a passage that current doesnot pass through the interior of the porous ceramic plate 340, itsresistance value is small. Thus, the current density becomes so highthat control for decreasing the plated film thickness in the vicinity ofthe outer peripheral portion of the substrate W may be impossible.

[0293] In this embodiment, therefore, a seal member 360 is providedbetween the porous ceramic plate 340 and the holding member 332, asshown in FIG. 50A. With this arrangement, leakage of the plating liquidfrom this portion is prevented so that the plated film thickness in thevicinity of the outer peripheral portion of the substrate W can becontrolled so as to be small.

[0294] The seal member 360 in this embodiment has an inverted L-shapedcross section, and is composed of an insulating material, and thus theseal member 360 also serves as the insulating member shown in FIG. 45.The seal member 360, as its cross section is shown in FIG. 50B, may beconstructed by attaching, as separate parts, an annular seal memberportion 360 a for sealing the portion at which the holding member 332and the lower surface of the porous ceramic plate 340 are in contactwith each other, and an insulating member portion 360 b exhibiting thesame function as the band-like insulating member 350 shown in FIG. 45.

[0295] The seal member 360, needless to say, can be applied to therespective embodiments other than the embodiment in FIG. 45.Specifically, more effective electric field control can be performed byjointly using the seal member 360 for preventing leakage of the platingliquid from a portion between the outer peripheral side surface of thehigh resistance structure 340 and the holding member 332, and electricfield control means according to other various embodiments.

[0296] [Embodiment in Which a Portion Without a High ResistanceStructure Interposed is Provided as Electric Field State Control Meansin a Portion Between a Anode and a Substrate, where the Current Densityis to be Increased]

[0297]FIG. 51 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment. In FIG. 51, unlike theembodiment shown in FIG. 45, the insulating member 350 is not mounted onthe outer periphery of the high resistance structure 340, but instead,the shape per se of the high resistance structure 340 is changed tocontrol the plated film thickness.

[0298]FIGS. 52A through 52D are plan views of the high resistancestructure 340 used in the electroplating apparatus shown in FIG. 51.That is, the high resistance structure 340 in this embodiment is, forexample, a porous ceramic plate 342. As shown in FIG. 52A, the outerperipheral shape of the porous ceramic plate 342 is polygonal, or asshown in FIG. 52B, the porous ceramic plate 342 is provided with slits365 at predetermined intervals, or as shown in FIG. 52C, the porousceramic plate 342 is wave-shaped (gear-shaped). On the other hand, theanode plate 338 and the substrate W are circular as indicated by aone-dot chain line, so that a portion, which is facing the anode plate338, with only the plating liquid 310 interposed, without the porousceramic plate 340 interposed, occurs near the outer periphery of thesubstrate W. In this portion, compared with the portion with the porousceramic plate 340 interposed, the electrical resistance between theanode plate 338 and the substrate W lowers, and the electrical densityin the outer peripheral portion of the substrate W increases. Hence,such embodiments can be utilized when it is desired to make the platedfilm thickness in the vicinity of the outer periphery of the substrate Wlarger than the plated film thickness near the center.

[0299] When the plated film thickness in other portions than the outerperipheral portion of the substrate W, such as the central portion ofthe substrate W, is controlled to be large, it is recommendable toprovide a hole 366 inside the porous ceramic plate 342, as shown in FIG.52D, thereby providing a portion where the porous ceramic plate 342 isnot interposed between the anode plate 338 and the substrate W.

[0300] In the electroplating apparatus shown in FIG. 51, the substrate Wis rotated, whereby plating with a uniform film thickness on the entiresurface of the substrate W can be performed. Instead of rotation of thesubstrate W, or along with rotation of the substrate W, the holdingmember 332 side may be rotated. Permission of rotation of the substrateW and/or the holding member 332 is not restricted to the embodimentshown in FIG. 51.

[0301] [Embodiment in Which Distribution is Imparted to the Thickness ofHigh Resistance Structure as Electric Field State Control Means]

[0302]FIG. 53 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. In the electroplating apparatus shown in FIG. 53, atwo-dimensional distribution is imparted to the thickness of the highresistance structure 342, whereby the current density distribution overthe surface of the substrate W is controlled to be a desired one tocontrol the plated film thickness. That is, in this embodiment, the highresistance structure 340 is, for example, a porous ceramic plate 342,and the porous ceramic plate 342 is circular and is adapted to bethinner at a central portion than at a peripheral portion. Because ofthis feature, the resistance value at the central portion between theanode plate 338 and the substrate W can be made lower than theresistance value at the peripheral portion. As described above,therefore, the plated film thickness, which tends to be smaller towardthe center, can be controlled to be uniform.

[0303]FIG. 54 is a view showing a comparison of the measured values ofthe plated film thickness when plating was performed on the substrate Wwith the use of the porous ceramic plate 40 having a uniform thicknessand the porous ceramic plate 40 having a thickness distribution as shownin FIG. 53. FIG. 54 shows that the use of the porous ceramic plate 342shown in FIG. 53 achieves the uniformity of the plated film thickness onthe substrate W. The same effect is obtained even when the porousceramic plate 342 shown in FIG. 53 is installed with an invertedstructure, as shown in FIG. 55.

[0304] Similarly, as shown in FIG. 56, the thickness of the porousceramic plate 342 at the center is made larger than the thickness at theperipheral portion, whereby the plated film thickness at the peripheralportion can be made greater than at the central portion. Alternatively,as shown in FIG. 57, a through-hole 367 is provided in the porousceramic plate 342, whereby the plated film thickness at the site wherethe through-hole 367 is provided may be larger than at other portions.Moreover, the plated film thickness in the vicinity of the outerperiphery of the substrate W may be made smaller than at other portionsby chamfering the outer peripheral corners of the porous ceramic plate342, as shown in FIG. 58, to make the electrical resistance at this sitelower than at other portions, whereby the plated film thickness at theperipheral portion can be made greater than at the central portion. In award, it is possible to control the plated metal thickness at portionsto desired one by imparting a distribution to the thickness (includingthickness =zero) of the high resistance structure 342.

[0305] [Embodiment in Which Distribution is Imparted to Pore Structureof Porous Substance as Electrical Field State Control Means]

[0306]FIG. 59 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. In the electroplating apparatus shown in FIG. 59, a poroussubstance (e.g., porous ceramic) 342 a with a pore structure having atwo-dimensional or three-dimensional distribution is used as the highresistance structure 340. The porous substance 342 a differs in theamount, and state of holding, of the plating liquid held therein,according to the diameter, number, state of arrangement, etc., of pores,and its resistance value varies accordingly. In this embodiment,therefore, the pore structure C1 in the vicinity of the center is madedifferent from the pore structure C2 in the vicinity of the outerperipheral portion, and the pore structure C1 in the vicinity of thecenter is made lower in resistance. According to this constitution, thecurrent density in the vicinity of the center increases, facilitatingthe formation of plating at this site. Needless to say, by contrast, thepore structure C2 in the vicinity of the outer peripheral portion can bemade lower in resistance to make the plated film thickness in thevicinity of the outer periphery greater. Furthermore, three types ormore of the pore structures may be used to perform more complicatedcontrol of the plated film thickness.

[0307] Methods of imparting distribution to the pore structure include amethod of imparting the distribution during integral molding of theporous substance 342 a as shown in FIG. 59, and a method of separatelyforming portions C1, C2 with different pore structures in the poroussubstance 342 a, and then integrating them by assemblage, as shown inFIGS. 60A and 60B.

[0308] The elements of the pore structure are pore diameter (e.g., thediameter varying in the range of 50 to 400 Ωm), continuous porosity(degree of air bubbles joined together . . . more joining decreases theresistance value), and flexing rate (degree of bending of the joinedpores in the thickness direction . . . less bending decreases theresistance value).

[0309] To make the pore structure different, the material per se, forexample, may be rendered different (e.g., resin-based material versusceramic-based material). As means for controlling the distribution ofthe porosity of the porous substance 342 a, sealing treatment of atleast part of the surface or interior of the porous substance 342 a(herein, porous ceramic) is available (a resin-based or silanol-basedcoating type insulating film is used, or SiC of a base material ispartially oxidized, etc.). There is also a method in which after uniformsealing treatment of the entire surface, some sealed portions are openedto change the pore distribution in the surface.

[0310] As materials for the porous substance 342 a, anisotropicstructural materials as shown in FIGS. 61A and 61B are also present.That is, they include a directional porous structural material as shownin FIG. 61A, and a fibrous porous structural material as shown in FIG.61B. The materials constituting these anisotropic structural materialsinclude resins and ceramics. In these anisotropic structural materials,the pores are joined together in a specific direction, and an electriccurrent easily flows in the specific direction (electric currentdifficultly flows in other directions), so that controllability of thecurrent density can be improved. By providing a difference between thepore structure C1 in the vicinity of the center and the pore structureC2 in the vicinity of the outer peripheral portion of the poroussubstance 342 a with the use of the anisotropic structural material, thecurrent density distribution applied to the surface of the substrate Wcan be formed into a desired one.

[0311] The embodiments of the present invention have been describedabove, but the present invention is not limited to these embodiments,but various modifications are possible within the scope of the claimsand within the scope of the technical ideas described in thespecification and drawings. Furthermore, any shapes or materials, whichare not directly described in the specification and drawings, fallwithin the scope of the technical ideas of the present invention, ifthey exhibit the actions and effects of the present invention.

[0312] For example, the above embodiments have shown examples in whichthe present invention has been applied to so-called face-up typeelectroplating apparatuses, but the present invention is also applicableto a so-called face-down type electroplating apparatus as shown in FIG.62. That is, this electroplating apparatus is constituted by including acupshaped plating tank 312 for holding a plating liquid 310, installinga disk-shaped anode plate 314 at the bottom of the plating tank 312,installing a disk-shaped high resistance structure 324 on the platingtank 312, arranging a plating liquid receiver 316 around the platingtank 312 for recovering the plating liquid 310 that has overflowed fromthe top of the plating tank 312, further placing a substrate W on a lipseal 318 provided above the plating tank 312, and bringing contacts 320into contact with the outer periphery of the lower surface of thesubstrate W.

[0313] A voltage is applied between the anode plate 314 and thesubstrate W to flow an electric current, while circulating the platingliquid through a through-hole 314 a provided at the center of the anodeplate 314 and small holes 324 a provided at the center of the highresistance structure 24. As a result, a plated film is formed on thelower surface of the substrate W.

[0314] In the respective embodiments, moreover, an insulating member ismounted on the outer periphery of the high resistance structure 324, orthe thickness of the high resistance structure is varied, or the porestructure thereof is changed, whereby the distribution of the platedfilm thickness formed on the substrate W can be made a desireddistribution.

[0315] Also, the present invention can be applied to a closed typeelectroplating apparatus as shown in FIG. 63. That is, this platingapparatus has a box-shaped plating tank 350. One opening end of thisplating tank 350 is closed with a anode plate 352, while the otheropening end thereof is openably and closably closed with a cover body354 holding a substrate W on the plating tank 350 side. Between thesubstrate W and the anode plate 352, a high resistance electrolyticsolution chamber 368 partitioned and formed by being sandwiched betweentwo diaphragms 360 a and 360 b held by two meshes 362 a and 362 b isinstalled as a high resistance structure 376.

[0316] A plating liquid 370 is introduced into a plating chamber 364,and an electrolytic solution (plating liquid) 372 is introduced into anelectrolytic solution chamber 366, respectively, and with these liquidsbeing circulated, a voltage is applied between the anode plate 352 andthe substrate W to flow an electric current. As a result, a plated filmis formed on the substrate W.

[0317] As in the respective embodiments, moreover, an insulating memberis mounted on the surface of the high resistance structure 376, or thesurfaces of the meshes 362 a, 362 b are processed to change the shape,such as thickness, of the high resistance electrolytic solution chamber368, whereby the distribution of the plated film thickness formed on thesubstrate W can be made a desired distribution.

[0318] As this sort of the diaphragms 360 a, 360 b, a strongly acidiccation exchange membrane, e.g., Tokuyama's CMS or Du Pont's N-350, isgenerally used. However, the selectivity of cations may be changed, orthe exchange membrane may be an anion exchange membrane or a nonionicexchange membrane. The electrolyte in the high resistance electrolyticsolution chamber 368 is generally (50 to 200 g/l) H₂SO₄ is used, but itis a matter of course that an arbitrary concentration can be selected,and the electrolyte is not restricted to sulfuric acid.

[0319] Furthermore, it goes without saying that the present invention isapplicable to electroplating apparatuses of other various structures(including both the face-up type and the face-down type). Besides, theabove respective embodiments have shown examples of the presentinvention applied to electroplating apparatuses, but instead, theinvention may be applied to an electrolytic etching apparatus using thesubstrate as anode.

[0320] In the above embodiments, a circular substrate to be treated hasbeen used, and all the electric field distributions are shown in aconcentric shape. However, the substrate to be treated may be of variousshapes other than the circular one, and the electric field distributionmay be a non-concentric shape, if necessary. For example, a plate-likeone (including a shape other than circle) such as LCD may be used as thesubstrate to be treated. The cathode contacts 336 may be ones, whichcontact the substrate to be treated, from one direction, in place ofring-shaped ones. Also, the cathode contacts 336 may be contacted with aposition other than the outer periphery of the substrate to be treated.

[0321] By so actively controlling the state of the electric field of thesurface of the member to be treated to be a desired state, the treatedstate by electrolytic treatment of the member to be treated can bebrought to a treated state of the desired distribution over the surface.

[0322] [Embodiment in Which Pipe 445 is Inserted in ElectrolyticSolution Introduction Hole (Plating Liquid Introduction Hole) 439 ofAnode Plate (Electrode) 438]

[0323]FIG. 64 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. That is, this electroplating apparatus is an electroplatingapparatus applying to so-called face-up type, in which a substrate W isplaced on a substrate placing stand 430 so as to face upward. A frontend of a ring-shaped lip seal 434 contacts the periphery of the surfaceof the substrate W to seal it. Outwardly of the lip seal 434 on thesurface of the substrate W, contacts 436 are disposed for contacting aconductive layer on the surface of the substrate W to apply a cathodepotential onto the substrate W. A disk-shaped porous body 440 and adisk-shaped anode plate 438 are disposed above the substrate W with apredetermined spacing therebetween, and held by a holding member 432.The anode plate 438 is provided with many plating liquid passing holes439 passing therethrough in the thickness direction. A plating liquidintroduction pipe 441 for supplying the plating liquid in a distributedmanner is provided on the anode plate 438.

[0324] On the other hand, the porous body 440 is constituted of a porousceramic material or a porous resin material. In this embodiment, theporous body 440 is an SiC plate, for example, having a porosity of 20%,an average pore diameter of 50 Ωm (of course, may be constituted of anyother material, but desirably has a pore diameter of 20 to 300 Ωm and aporosity of 10 to 95%), and holding a plating liquid 410 therein, andself-holding it. Thus, the porous body 440 is adapted to passelectricity, but have a lower electrical conductivity than that of theplating liquid 410. The anode plate 438 is of a structure completelycovered with the holding member 432 and the porous body 440.

[0325] In this embodiment, a plating liquid introduction pipe 441 areprovided with pipes 445 communicating with a plating liquid introductionpipe 441 per se, the pipes 445 are inserted into plating liquidintroduction holes 439 of a anode plate 438, and the front ends of thepipes 445 are brought into contact with the surface of the porous body440. That is, in this embodiment, the plating liquid can be supplied tothe surface of the porous body 440 without causing the plating liquid tocontact the anode 438 at all. The plating liquid introduction pipe 441and the pipes 445 are integrally formed by a synthetic resin of amaterial which is not affected at all by the plating liquid.

[0326] The plating liquid, which has been directly supplied to thesurface of the porous body 440 from the plating liquid introduction pipe441 through the pipes 445, reaches the surface of the substrate W whilethe plating liquid is slightly diffusing in the porous body 440, and theplating liquid forms a plurality of circular plating liquid columns Rbetween the substrate W and the surface of the porous body 440, and theplural plating liquid columns R bind to each other on the substrate W,thus filling the surface of the substrate W with the plating liquid.

[0327] Even when this plating step is repeated, the inner diameter ofthe front end of the pipe 445 does not increase with the passage oftime, and hence the ideal plating liquid columns R do not collapse withthe passage of time. Consequently, engulfment of air due to disturbanceof binding of the plating liquid columns R does not take place. Airbubbles are not accumulated between the porous body 440 and thesubstrate W, and the plated film thickness does not become non-uniform.

[0328]FIG. 65 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. This electroplating apparatus differs from that in theembodiment shown in FIG. 64 in that instead of forming pipes 445integrally with a plating liquid introduction pipe 441, separatelyprepared pipes 447 are inserted into plating liquid introduction holes439 of the anode plate 438. In this case also, the pipes 447 arecomposed of a material that is not affected at all by the platingliquid, and the front ends (lower ends) of the pipes 447 are broughtinto contact with the upper surface of the porous body 440.

[0329] Even with this constitution, the plating liquid does not directlycontact the anode plate 438 in the same manner as the embodiment shownin FIG. 64. Even when the plating step is performed repeatedly, theinner diameter of the front end of the pipe 447 does not increase withthe passage of time. Thus, the plating liquid columns R supplied fromthe porous body 440 do not collapse with the passage of time, but can bealways kept in the ideal state, and engulfment of air does not occur.

[0330] [Embodiment in Which Electrolytic Solution Passage Portions areProvided in Porous Body 440]

[0331]FIG. 66 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. In this electroplating apparatus, the plating liquidintroduction pipe 441 shown in FIG. 64 is not provided, but an anodeplate 438 and a porous body 440 (440 a, 440 b) are held by a holdingmember 432. A liquid reservoir 450 is provided between the anode plate438 and the porous body 440. That is, a plurality of thin plating liquidpassing holes 439 as shown in FIG. 64 are not provided, but one thickplating liquid supply portion 455 is provided at the center.

[0332] On the other hand, the porous body 440 is composed of two members(upper porous body 440 a and lower porous body 440 b) laying the top andbottom. The upper porous body 440 a is provided with a plurality of thinelectrolytic solution passage portions 457 leading to upper and lowersurfaces. The electrolytic solution passage portion 457 is formed byconstituting portions, which serve as the electrolytic solution passageportions 457, made of a material having a low density (high porosity)porous structure, and constituting all of other portions made of amaterial having a high density porous structure. The lower porous body440 b is constituted entirely of a material having a low density porousstructure.

[0333] According to this constitution, when the plating liquid issupplied from the plating liquid supply portion 455 of the anode plate438, the plating liquid 410 is first filled into the liquid reservoir450. Then, the plating liquid 410 passes mainly through the electrolyticsolution passage portions 457 with low resistance, arriving at thesurface of the lower porous body 440 b. Further, the plating liquid 410reaches the surface of the substrate W while diffusing inside the lowerporous body 440 b. This plating liquid forms a plurality of circularplating liquid columns R between the substrate W and the surface of thelower porous body 440 b. The plural plating liquid columns R bind toeach other on the substrate W, thus filling the surface of the substrateW with the plating liquid while expelling air.

[0334] Even when this plating step is repeated, the inner diameter ofthe front end of the electrolytic solution passage portion 457 does notincrease with the passage of time, and hence the ideal plating liquidcolumns R do not collapse with the passage of time. Consequently,engulfment of air due to disturbance of binding of the plating liquidcolumns R does not take place. Air bubbles are not accumulated betweenthe lower porous body 440 b and the substrate W, and the plated filmthickness does not become non-uniform.

[0335]FIG. 67 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. The difference of this electroplating apparatus from theembodiment shown in FIG. 66 is only in the structure of the porous body440. That is, in this porous body 440, electrolytic solution passageportions 459 comprising holes are provided in its interior. Theelectrolytic solution passage portions 459 are formed as branches from amain passage 461 provided in the center of the upper surface of theporous body 440. The front end of each electrolytic solution passageportion 459 ends inside the porous body 440.

[0336] When the plating liquid is supplied from the plating liquidsupply portion 455 of the anode plate 438, the plating liquid 410 isfirst filled into the liquid reservoir 450. Then, the plating liquid 410is introduced into the respective electrolytic solution passage portions459 from the main passage 461 of the porous body 440. From the lowerends of the electrolytic solution passage portions 459, the platingliquid 410 reaches the surface of the substrate W while diffusing in theporous body 440. This plating liquid forms a plurality of circularplating liquid columns R between the substrate W and the surface of theporous body 440. The plural plating liquid columns R bind to each otheron the substrate W, thus filling the surface of the substrate W with theplating liquid.

[0337] Even when this plating step is repeated, the inner diameter ofthe front end of the electrolytic solution passage portion 459 does notincrease with the passage of time, and hence the ideal plating liquidcolumns R do not collapse with the passage of time. Consequently,engulfment of air due to disturbance of binding of the plating liquidcolumns R does not take place. Air bubbles are not accumulated betweenthe porous body 440 and the substrate W, and the plated film thicknessdoes not become non-uniform.

[0338] By adjusting the position of the front end (bottom surface) ofthe electrolytic solution passage portion 459, the distance from thefront end of the electrolytic solution passage portion 459 to the lowersurface of the porous body 440 can be shortened. As a result, theresistance can be reduced during the plating liquid is passing throughthe porous body 440. Thus, even when the porous body 440 having a largethickness or a high density (low porosity) is used, the resistanceduring passage of the plating liquid through the porous body 40 forliquid filling can be made low. Thus, an appropriate amount of theplating liquid can be fed from a predetermined position of the porousbody 440. Because of this feature as well, engulfment of air due todisturbance of binding of the plating liquid columns R does not takeplace. Air bubbles are not accumulated between the porous body 440 andthe substrate W, and the plated film thickness does not becomenon-uniform.

[0339] It is difficult to form the electrolytic solution passageportions 459 comprising holes in the porous body 440. Thus, the porousbody 440 divided into three parts at lines A and B shown in FIG. 67 maybe prepared, and the three parts may be integrated by bonding and fixingto constitute the electrolytic solution passage portions 459.

[0340] [Embodiment in Which Pipes are Inserted into Plating LiquidIntroduction Holes (Electrolytic Solution Introduction Holes) 439 ofAnode Plate 438 and Electrolytic Solution Passage Portions 459 areProvided in Porous Body 440]

[0341]FIG. 68 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. In this electroplating apparatus, like the embodiment shownin FIG. 64, pipes 445 communicating with a plating liquid introductionpipe 441 of synthetic resin (a material unaffected by the platingliquid) are provided in the plating liquid introduction pipe 441 per se,the pipes 445 are inserted into plating liquid passing holes 439 of aanode plate 438, and the front end of each pipe 445 is contacted withthe surface of a porous body 440. Moreover, electrolytic solutionpassage portions 459 comprising narrow holes not being through-holes areprovided in a portion of the porous body 440 which is contacted with thepipes 445.

[0342] The plating liquid, which has been directly supplied into theelectrolytic solution passage portions 459 of the porous body 440 fromthe plating liquid introduction pipe 441 through the pipes 445,permeates through the porous body 440 from the bottom surface of theelectrolytic solution passage portions 459 while slightly diffusing inthe porous body 440, and reaches the surface of the substrate W. Thisplating liquid forms a plurality of circular plating liquid columns Rbetween the substrate W and the surface of the porous body 440. Theplural plating liquid columns R bind to each other on the substrate W,thus filling the surface of the substrate W with the plating liquidwhile forcing air outward.

[0343] Even when this plating step is performed repeatedly, neither theinner diameter of the front end of the pipe 445 nor the inner diameterof the bottom surface of the electrolytic solution passage portion 459does not increase with the passage of time, and hence the ideal platingliquid columns R do not collapse with the passage of time. Consequently,engulfment of air due to disturbance of binding of the plating liquidcolumns R does not take place. Air bubbles are not accumulated betweenthe porous body 440 and the substrate W, and the plated film thicknessdoes not become non-uniform.

[0344] At the same time, the resistance during passage of the platingliquid through the porous body 440 can be decreased in an amountcorresponding to the length of the electrolytic solution passage portion459. Thus, even when the porous body 440 having a large thickness or ahigh density (low porosity) is used, an appropriate amount of theplating liquid can be fed from a predetermined position of the porousbody 440 while the plating liquid is introduced. Because of this featureas well, engulfment of air due to disturbance of binding of the platingliquid columns R does not take place. Air bubbles are not accumulatedbetween the porous body 440 and the substrate W, and the plated filmthickness does not become non-uniform.

[0345]FIG. 69 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. The difference of this electroplating apparatus from theembodiment shown in FIG. 68 is that instead of forming the pipes 445 andthe plating liquid introduction pipe 441 integrally therewith,separately prepared pipes 447 are inserted into the plating liquidpassing holes 439 of the anode plate 438 and the electrolytic solutionpassage portions 459 provided in the porous body 440. In this case aswell, the pipes 447 are composed of a material unaffected by the platingliquid.

[0346] According to this constitution, like the embodiment shown in FIG.68, even when the plating step is performed repeatedly, the innerdiameter of the front end of the pipe 447 does not increase with thepassage of time, and the ideal plating liquid columns R do not collapsewith the passage of time. Consequently, engulfment of air due todisturbance of binding of the plating liquid columns R does not takeplace. Air bubbles are not accumulated between the porous body 440 andthe substrate W, and the plated film thickness does not becomenon-uniform. At the same time, the pipes 447 protrude into the porousbody 440. Thus, the resistance during passage of the plating liquidthrough the porous body 440 can be decreased. Even when the porous body440 having a large thickness or a high density (low porosity) is used,an appropriate amount of the plating liquid can be fed from apredetermined position of the porous body 440. Hence, engulfment of airdue to disturbance of binding of the plating liquid columns R does nottake place. Air bubbles are not accumulated between the porous body 440and the substrate W and the plated film thickness does not becomenon-uniform.

[0347] [Embodiment in Which Passage Resistance During Passage of PlatingLiquid Through Porous Body 440 is Made Different According to theLocation of Porous Body 440]

[0348]FIG. 70 is a schematic constitution drawing of an electroplatingapparatus according to still another embodiment of the presentinvention. In this electroplating apparatus, like the embodiment shownin FIG. 64, a plating liquid introduction pipe 441 of synthetic resinare provided with pipes 445 communicating with a plating liquidintroduction pipe 441 per se. However, unlike FIG. 64, a anode plate 438is convex, while a porous body 440 is concave, at the center of thesurface of bonding between the anode plate 438 and the porous body 440.By so constituting, the plating liquid supplied from the pipes 445 inthe vicinity of the center is fed from the lower surface of the porousbody 440 with a decreased passage resistance, so that its amountsupplied is larger than that fed at other portions. In other words, incase a desired plating liquid does not exit depending on the location,the passage resistance of the plating liquid through the porous body 440at that site is decreased so that the desired plating liquid can exit atthat site as well (an appropriate amount of the plating liquid may bedifferent according to the location of the porous body 440). By sodoing, disturbance of binding of the plating liquid columns R isprevented to prevent engulfment of air, thereby preventing air bubblesfrom accumulating between the porous body 440 and the substrate W tomake the plated film thickness non-uniform.

[0349] Such adjustment can be achieved, for example, by making thepositions of the bottoms of the electrolytic solution passage portions459 shown in FIGS. 68 and 69 different in the respective electrolyticsolution passage portions 459. That is, the passage resistance of theplating liquid passing through the porous body 440 is made differentaccording to the location. By this measure, the amounts of the platingliquid supplied from the respective portions of the porous body 440 canbe varied, and the optimal state of filling with the plating liquid canbe selected.

[0350] The respective embodiments show examples of application toelectroplating apparatuses. Instead, the present invention may beapplied to an electrolytic etching apparatus using a substrate as ananode.

[0351] A detailed description has been offered above of electrolytictreatment apparatuses of a structure, in which an electrolytic solutionis supplied into an electrolytic solution impregnated material and fedfrom the opposite side of the electrolytic solution impregnated materialto fill the electrolytic solution between the electrolytic solutionimpregnated material and a substrate to be treated. Even suchelectrolytic treatment apparatuses do not face the situation that airbubbles are engulfed between the electrolytic solution impregnatedmaterial and the substrate to be treated, and are accumulated betweenthem. The apparatuses exhibit the excellent effect that ideal liquidfilling is performed to achieve desired electrolytic treatment.

What is claimed is:
 1. A plating apparatus for a substrate, comprising:a substrate holding portion for holding the substrate such that asurface, to be plated, thereof faces upward; a cathode electrode forcausing current to flow by being in contact with the substrate; an anodepositioned above the surface, to be plated, of the substrate; andplating liquid pouring means for pouring a plating liquid into a spacebetween the surface, to be plated, of the substrate held by saidsubstrate holding portion and said anode brought close to the surface tobe plated.
 2. The plating apparatus for a substrate according to claim1, wherein a plating liquid impregnated material composed of a waterretaining material is contacted with and held on a lower surface of saidanode.
 3. The plating apparatus for a substrate according to claim 1,comprising: a cathode portion; and a plating liquid tray disposedlaterally of said cathode portion; wherein said anode is movable betweensaid cathode portion and said plating liquid tray.
 4. The platingapparatus for a substrate according to claim 1, comprising: a cathodeportion; and a plurality of nozzles disposed laterally of said cathodeportion; wherein said nozzles jet a pretreatment liquid, a cleaningliquid, a gas or the like toward the surface, to be plated, of thesubstrate held by said substrate holding portion.
 5. The platingapparatus for a substrate according to claim 1, comprising a cathodeportion; wherein said substrate holding portion is capable of ascendingand descending between a lower substrate transfer position, an upperplating position where a peripheral edge portion of the surface, to beplated, of the substrate contacts said cathode portion, and apretreatment/cleaning position being intermediate between thesepositions.
 6. A plating method for a substrate, comprising: sealing aperipheral edge portion of a surface, to be plated, of the substrate ina watertight manner, the surface, to be plated, of the substrate facingupward and being electrically connected to a cathode electrode;positioning an anode closely above the surface, to be plated, of thesubstrate; and pouring a plating liquid into a sealed space between thesurface, to be plated, of the substrate and said anode.
 7. A platingmethod for a substrate, characterized by recovering a remaining platingliquid by a plating liquid recovering nozzle after plating as recited inclaim
 6. 8. The plating method for a substrate according to claim 6,comprising: moving a pre-coating/recovering arm to a position facing thesubstrate before plating; and supplying a pre-coating liquid from apre-coating nozzle to perform pre-coating treatment.
 9. The platingmethod for a substrate according to claim 6, comprising: positioning aplating liquid impregnated material composed of a water retainingmaterial in a space between a surface, to be plated, of the substrateand said anode; and holding the plating liquid inside said platingliquid impregnated material.
 10. A plating apparatus for a substrate,comprising: an anode positioned above a surface, to be plated, of thesubstrate held by a substrate holding portion; and a cathode electrodefor causing current to flow by being in contact with the substrate;wherein a plating liquid impregnated material composed of a waterretaining material is positioned in a space between the surface to beplated of the substrate, and said anode to perform plating.
 11. Theplating apparatus for a substrate according to claim 10, wherein saidplating liquid impregnated material is a high resistance structure. 12.The plating apparatus for a substrate according to claim 10, whereinsaid plating liquid impregnated material comprises a ceramic.
 13. Aplating apparatus for a substrate, characterized by performing plating asurface, to be plated, of the substrate in such state that the platingliquid impregnated material is out of contact with the surface, to beplated, of the substrate, and a plating liquid is filled into a gapbetween said plating liquid impregnated material and the surface, to beplated, of the substrate.
 14. A plating apparatus for a substrate,characterized by performing plating treatment, and cleaning/dryingtreatment in a single unit by raising and lowering the substrate so asto correspond to respective operating positions, with the substratebeing held by a substrate holding portion.
 15. The plating apparatus fora substrate according to claim 14, comprising: an anode positioned abovea surface, to be plated, of the substrate; and a cathode electrode forcausing current to flow by being in contact with the substrate; whereina plating liquid impregnated material composed of a water retainingmaterial is positioned in a space between the surface, to be plated, ofthe substrate and said anode.
 16. A plating method for a substrate,comprising: transferring the substrate into a plating unit by a transferrobot after withdrawing the substrate from a loading/unloading unithousing the substrate; holding the substrate by a substrate holdingportion in said plating unit; and performing treatments in a single unitby raising and lowering the substrate so as to correspond to respectiveoperating positions for performing plating treatment and cleaning/dryingtreatment, with the substrate being held by said substrate holdingportion.
 17. A plating apparatus for a substrate, comprising: aloading/unloading unit housing the substrate; a plating unit forperforming plating treatment and treatment incidental thereto in asingle unit; and a transfer robot for transferring the substrate betweensaid loading/unloading unit and said plating unit.
 18. A platingapparatus for a substrate, comprising: an anode positioned above asurface, to be plated, of the substrate held by a substrate holdingportion; a cathode electrode for causing current to flow by being incontact with the substrate; and a pure water supply nozzle; wherein thesubstrate and said cathode electrode are simultaneously cleaned bysupplying pure water from said nozzle after completion of plating.
 19. Aplating apparatus for a substrate, comprising: a substrate holdingportion for holding the substrate; a cathode electrode for causingcurrent to flow by being in contact with the substrate held by saidsubstrate holding portion; an anode positioned closely to the substrate;and plating liquid pouring means for pouring a plating liquid into aspace between the surface, to be plated, of the substrate held by saidsubstrate holding portion and said anode brought close to the surface tobe plated; wherein said plating liquid pouring means is constituted suchthat the plating liquid is poured between said anode and the surface, tobe plated, of the substrate from a plating liquid pouring path providedin part of said anode or provided around an outer peripheral portion ofsaid anode, and is spread on the surface, to be plated, of thesubstrate.
 20. The plating apparatus for a substrate accorging to claim19, comprising: the substrate holding portion for holding the substratesuch that a surface, to be placed, thereof faces upward; a seal materialfor holding the plating liquid on the surface, to be plated, of thesubstrate held by said substrate holding portion; a cathode portionhaving a cathode electrode for causing current to flow by being incontact with the substrate; an electrode arm portion, having an anode,movable horizontally and vertically in proximity to said cathodeelectrode; and plating liquid pouring means for pouring a plating liquidinto a space between the surface, to be plated, of the substrate held bysaid substrate holding portion and said anode brought close to thesurface to be plated; wherein said plating liquid pouring means isconstituted such that the plating liquid is poured between said anodeand the surface, to be plated, of the substrate from a plating liquidpouring hole provided through part of said anode or a nozzle providedaround the outer peripheral portion of said anode, and is spread on thesurface, to be plated, of the substrate.
 21. The plating apparatus for asubstrate according to claim 20, wherein said plating liquid pouringmeans has a plating liquid introduction path which is provided along adiametrical direction of said anode on a surface of said anode oppositeto a surface, facing the substrate, of the anode, and is connected to aplating liquid supply pipe, and said plating liquid pouring hole isprovided at a position facing a plating liquid introduction holeprovided so as to open toward a surface of said plating liquidintroduction path located at said anode side.
 22. The plating apparatusfor a substrate according to claim 19, wherein said plating liquidpouring means has a plating liquid introduction path which is providedin a cruciform, radial or circumferential form on a surface of saidanode opposite to a surface, facing the substrate, of the anode, and isconnected to a plating liquid supply pipe, and said plating liquidpouring hole is provided at a position facing a plating liquidintroduction hole provided so as to open toward a surface of saidplating liquid introduction path located at said anode side.
 23. Aplating method for a substrate, comprising: positioning an anode closelyto at least part of a surface, to be plated, of the substrate which iselectrically connected to a cathode electrode; and pouring a platingliquid between the surface, to be plated, of the substrate and saidanode, wherein a plating liquid column which bridges the surface, to beplated, of the substrate and said anode is formed and the plating liquidis poured with said plating liquid column as a starting point.
 24. Theplating method for a substrate according to claim 23, wherein theplating liquid is poured between the surface, to be plated, of thesubstrate and said anode from a plating liquid pouring path provided inpart of said anode or provided around an outer peripheral portion ofsaid anode.
 25. A plating method for a substrate, comprising:positioning an anode closely to at least part of a surface, to beplated, of the substrate which is electrically connected to a cathodeelectrode; and filling a plating liquid into a space between thesurface, to be plated, of the substrate and said anode, by covering theplating liquid on the surface, to be plated, of the substrate, andbringing the substrate and said anode close to each other graduallyunder relative rotation.
 26. The plating method for a substrateaccording to claim 25, wherein a plating liquid impregnated materialcomposed of a porous substrate having water retaining properties isplaced on a surface of a anode facing the substrate; and means forspreading the plating liquid between said plating liquid impregnatedmaterial and the substrate radially outwardly by relative rotation ofsaid plating liquid impregnated material and the substrate is providedon a surface of said plating liquid impregnated material facing thesubstrate.
 27. An electrolytic treatment method, characterized in that ahigh resistance structure is provided in at least part of anelectrolytic solution filled between a substrate, to be treated, havinga contact with one of electrodes consisting of an anode and a cathode,and the other electrode facing the substrate, to be treated, to performelectrolytic treatment of the surface of the substrate to be treated,the high resistance structure having an electrical conductivity lowerthan that of the electrolytic solution.
 28. The electrolytic treatmentmethod according to claim 27, wherein said high resistance structure isconstituted such that a resistance thereof in an equivalent circuit ishigher than a resistance in the equivalent circuit between the contactwith the electrode on a conductive layer formed on the surface of thesubstrate to be treated and a portion electrically farthest from saidcontact.
 29. The electrolytic treatment method according to claim 27,wherein said electrolytic treatment is performed in such a state thatsubstrate is held face-up by a substrate holding portion.
 30. Anelectrolytic treatment apparatus for performing electrolytic treatmentof a substrate, to be treated, by filling an electrolytic solutionbetween the substrate, to be treated, having a contact with one ofelectrodes consisting of an anode and a cathode, and the other electrodefacing the substrate to be treated, characterized in that a highresistance structure having an electrical conductivity lower than thatof the electrolytic solution is provided in at least part of theelectrolytic solution.
 31. The electrolytic treatment apparatusaccording to claim 30, wherein said electrolytic treatment is performedin such a state that substrate is held face-up by a substrate holdingportion.
 32. The electrolytic treatment apparatus according to claim 30,wherein said high resistance structure is constituted such that aresistance thereof in an equivalent circuit is higher than a resistancein the equivalent circuit between the contact with the electrode on aconductive layer formed on the surface of the substrate to be treatedand a portion electrically farthest said the contact.
 33. Theelectrolytic treatment apparatus according to claim 30, wherein saidhigh resistance structure comprises a porous substance holding anelectrolytic solution therein.
 34. The electrolytic treatment apparatusaccording to claim 33, wherein said porous substance comprises a porousceramic.
 35. The electrolytic treatment apparatus according to claim 30,wherein said high resistance structure is provided so as to divide theelectrolytic solution into a plurality of parts.
 36. A method forcontrolling an electric field state in an electrolytic treatmentapparatus, comprising: providing a high resistance structure in at leastpart of an electrolytic solution filled between a substrate, to betreated, having a contact with one of electrodes consisting of an anodeand a cathode, and the other electrode facing the substrate to betreated, said high resistance structure having an electricalconductivity lower than that of the electrolytic solution; andcontrolling an electric field of a surface of the substrate, to betreated, by adjusting at least one of an exterior shape of said highresistance structure, an internal structure of said high resistancestructure, and an attachment of a member having a different electricalconductivity.
 37. The method of controlling an electric field state inan electrolytic treatment apparatus according to claim 36, wherein saidadjusting of the exterior shape is at least one of adjustment of athickness of said high resistance structure, and adjustment of a shapeon a plane of said high resistance structure.
 38. The method ofcontrolling an electric field state in an electrolytic treatmentapparatus according to claim 36, wherein said high resistance structurecomprises a porous substance, and said adjusting of the internalstructure of said porous substance is at least one of adjustment of apore diameter distribution thereof, adjustment of porosity distributionthereof, adjustment of flexing rate distribution thereof, and adjustmentof a combination of materials.
 39. The method of controlling an electricfield state in an electrolytic treatment apparatus according to claim36, wherein said adjusting of the attachment of said member having thedifferent electrical conductivity is adjustment of a shielding area ofsaid high resistance structure by means of said member having thedifferent electrical conductivity.
 40. An electrolytic treatmentapparatus for performing electrolytic treatment of a substrate, to betreated, by filling an electrolytic solution between the substrate, tobe treated, having a contact with one of electrodes consisting of ananode and a cathode, and the other electrode facing the substrate to betreated, characterized in that: a high resistance structure, having anelectrical conductivity lower than that of the electrolytic solution, isprovided in at least part of the electrolytic solution; and an electricfield of a surface of the substrate, to be treated, is controlled byadjusting at least one of an exterior shape of said high resistancestructure, an internal structure of said high resistance structure, andan attachment of a member having a different electrical conductivity.41. The electrolytic treatment apparatus according to claim 40, whereinsaid adjusting of the exterior shape is at least one of adjustment of athickness of said high resistance structure, and adjustment of a shapeon a plane of said high resistance structure.
 42. The electrolytictreatment apparatus according to claim 40, wherein said high resistancestructure comprises a porous substance, and said adjusting of theinternal structure of said porous substance is at least one ofadjustment of a pore diameter distribution thereof, adjustment ofporosity distribution thereof, adjustment of flexing rate distributionthereof, and adjustment of a combination of materials.
 43. Theelectrolytic treatment apparatus according to claim 40, wherein saidadjusting of the attachment of said member having the differentelectrical conductivity is adjustment of a shielding area of said highresistance structure by means of said member having the differentelectrical conductivity.
 44. An electrolytic treatment apparatus forperforming electrolytic treatment of a substrate, to be treated, byfilling an electrolytic solution between the substrate, to be treated,having a contact with one of electrodes consisting of an anode and acathode, and the other electrode facing the substrate to be treated,characterized in that: a high resistance structure, having an electricalconductivity lower than that of the electrolytic solution, is providedin at least part of the electrolytic solution; an outer periphery ofsaid high resistance structure is held by a holding member; and a sealmember is provided between said high resistance structure and saidholding member for preventing the electrolytic solution from leakingtherethrough and preventing an electric current from flowing.
 45. Anelectrolytic treatment apparatus for performing electrolytic treatmentof a substrate, to be treated, by filling an electrolytic solutionbetween the substrate, to be treated, having a contact with one ofelectrodes consisting of an anode and a cathode, and the other electrodefacing the substrate to be treated, characterized in that: anelectrolytic solution impregnated material is disposed between saidother electrode and the substrate to be treated; an electrolyticsolution passing hole is provided in said other electrode for supplyingthe electrolytic solution into said electrolytic solution impregnatedmaterial; a pipe is inserted into said electrolytic solution passingholes; and the electrolytic solution supplied into said electrolyticsolution impregnated material through said pipe is supplied from anopposite surface of the electrolytic solution impregnated material andfilled between said electrolytic solution impregnated material and thesubstrate to be treated.
 46. The electrolytic treatment apparatusaccording to claim 45, wherein a electrolytic solution passage portionis provided in said electrolytic solution impregnated material so as tocontinue to said electrolytic solution passing hole.
 47. An electrolytictreatment apparatus for performing electrolytic treatment of asubstrate, to be treated, by filling an electrolytic solution betweenthe substrate, to be treated, having a contact with one of electrodesconsisting of an anode and a cathode, and the other electrode facing thesubstrate to be treated, characterized in that: an electrolytic solutionimpregnated material is disposed between said other electrode and thesubstrate to be treated; an electrolytic solution passage portion,having a predetermined depth, is formed in said electrolytic solutionimpregnated material; and the electrolytic solution supplied from saidother electrode side into said electrolytic solution impregnatedmaterial through said electrolytic solution passage portion is suppliedfrom an opposite surface of said electrolytic solution impregnatedmaterial and filled between said electrolytic solution impregnatedmaterial and the substrate to be treated.
 48. The electrolytic treatmentapparatus according to claim 47, wherein a liquid reservoir for storingthe electrolytic solution is provided between said other electrode andsaid electrolytic solution impregnated material, and the electrolyticsolution stored in said liquid reservoir is supplied into saidelectrolytic solution impregnated material.
 49. An electrolytictreatment apparatus for performing electrolytic treatment of asubstrate, to be treated, by filling an electrolytic solution betweenthe substrate, to be treated, having a contact with one of electrodesconsisting of an anode and a cathode, and the other electrode facing thesubstrate to be treated, characterized in that: an electrolytic solutionimpregnated material is disposed between said other electrode and thesubstrate to be treated; said electrolytic solution impregnated materialis constituted such that a passage resistance of the electrolyticsolution passing through said electrolytic solution impregnated materialdiffers according to a location of said electrolytic solutionimpregnated material; and the electrolytic solution supplied from saidother electrode side into said electrolytic solution impregnatedmaterial is supplied from an opposite surface of said electrolyticsolution impregnated material in a supply amount adapted for thelocation, and filled between said electrolytic solution impregnatedmaterial and the substrate to be treated.